An unauthorized sequel is a work created with the unauthorized use of another fan's story/universe/character. They are sometimes the subject of controversy and discussion in fandom.
Some fans feel that any fan story is fair game to be used; others feel it should require specific permission until a shared universe is a certain (indeterminate) size, or has been declared open by the original author.
In 2017, Ruth Berman commented on writing sequels to other fan stories: "I suspect that the habit of thinking about someone else’s story and finding that the thoughts are turning into scenes & dialogue demanding to be written as a separate story is related to the impulse to write stories in other people’s universes in the first place. It’s a sort of hybrid between fiction and criticism." 
A Double Standard?Some fans object to fans requiring permission from other fans to use their ideas when those same fans never asked the original creators of the canon:
There's a possible objection that I've seen raised to this requirement for permission, namely that we aren't bothering to ask permission of Brian Clemens or any of the other copyright owners and creators whose work we are appropriating, sometimes even over their protests. But I think the situation between fan writers is entirely different. For one thing, we are not in competition with Brian Clemens. What we do with his characters does not affect the way they are generally perceived; while an out-of-tune sequel, if not identified as unofficial, may disrupt the reception of further stories the original author wanted to circulate in that timeline. Also, there's little danger of people not knowing what was due to Clemens or whoever and what is original to the author; but there is a risk that fan writers will be Identified with stories they didn't write. (If someone wrote a sequel to a story of mine and didn't indicate on it that she wasn't me, I would be upset, because of the risk that people who had read the first one would assume that I wrote the second too. This would be true even if I liked the sequel. 
Some Examples of Fan Author's BansNot all fanfic writers are willing to share, even going so far as to threaten other fans with "copyright infringement." In 1978, here was a personal statement from Fern Marder and Carol Walske complaining about copyright infringement on the characters/universe they have created:
In 1976, a group of writers warned others:There is a relatively new fanzine available, called Antithesis, which deals with the Klingon Empire. The first issue contains material by the zine's editor, P. Spath, which bears close resemblance to details of our Klingon series, Nu Ormenel. We have been assured by Ms. Spath that these similarities are purely coincidental and that she has drawn her material from other sources and her imagination. We are willing to accept her word for this. In view of this situation, however, we would like to make a few comments with reference to the 'Nu Ormenel' material. All works in the 'Nu Ormenel' series have been copyrighted to us, either directly or through the editors of the fanzines in which they appeared. Therefore, the use by any other authors of any 'Nu Ormenel' data about Klingons, our characters, original vocabulary, and proper names, is an infringement of our copyright and will be dealt with accordingly.  Any work regarding Klingons which is not identified as part of the 'Nu Ormenel' series, and/or which is not written by one or both of us, IS NOT part of 'Nu Ormenel.' We have not given our permission for anyone to write and publish stories in our series, nor do we plan to in the future. Any story which contains material from 'Nu Ormenel', be it labeled as such or not, has been published contrary to our wishes and to the copyright laws. 
Devra Langsam comments on the Nu Ormenel restrictions:The Universes appearing herein appeared here because their authors volunteered them. I know that there are a couple of people who were leary [sic] of doing this at first - the reason being that there is a tendency in fandom for "free-lance" writers to pick up other people's universes and begin writing stories about for/about them, often without the original [a]authors' consent or even knowledge. Let this be a word to the wize [sic]: All the universes contained herein are covered under legal copyright; unauthorized writers for these universes will be dealt with accordingly. 
In 1978, Devra Langsam also warned other writers about "her" Klingons:There are several factors which make their writing different from that of the average trekwriter. 1.)Their stories are set 25 years into the future of ST. In fact, Kirk and Spock only appear in ONE of their stories. 2.)Fern and Carol have done their homework and created an entire Klingon culture, completely separate and different from the regular ST material—including history, law, folktales, three languages (plus archaic forms of these), and different alphabets for these scripts. 3.)This material has been amassed for the past ten years—ever since Carol first saw "Errand of Mercy". It is in no way to be considered a theft from Roddenberry. It is ALL original material. 4.) If the characters had not been called Klingons, and described as looking like Klingons, and shown so in the pictures, you would have had NO way of knowing that they had any relationship to ST at all. Regular sf is chock-full of evil Empires, virtuous Federations, Confederations, Galactic Unions—You can't say Roddenberry made up the idea of a Federation, any more than you can say that Lucas made up the idea of an evil Empire. I do NOT find it unreasonable that they should want to prevent the appearance of unauthorized, unapproved stories using their characters, their culture, their language, their ideas. They just plain donft want anybody writing about THEIR Klingons. Mind you, they never said they owned all Klingons, just the ones they made up. This sounds reasonable to me. I speak as someone who one day received a story which another writer had written about one of MY characters. This story completely screwed up all the ideas I'd been making, and absolutely destroyed the character I had created. (But she said it was a sequel to my story...) The other person thought it was a wonderful sequel, despite the fact that HER story totally reversed the major idea that I was putting forth in my story. I was furious. You may think that you know where an author's going, but ten to one you don't. Someone once read one of my stories and said, "I know! Janet's going to marry Master Kinet!"—an idea which gives me cold shudders. No one has the right to say, "Only I can write about Vulcans (Andorians, Tholians, Orions...)'1 The problem comes when someone writes so bloody well that others want to borrow the ideas. It may be flattering, but if the author doesn't want it, then it should be no dice. Some authors are flattered by others' wanting to participate in their universes; others don't want it. It shouldn't be necessary for an author to do anything more than say "No". Let's not have any of this nonsense about "GR made it all up in the beginning, and I can use anything that anyone else did SINCE then, because it's all part of the same thing". You have a right to what you've created, and other people ought to respect and recognize it. 
In 1989, Jean Lorrah explained why she didn't want other fans to write in the Epilogue universe:KLINGS—The first thing I want to point out about my Klingon stories is that they are NOT nu Ormenel Klingons. These are my own Klingons, and have no relationship to those of Carol Walske and Fern Marder.... I don't mind other people playing around with the ideas in my story, or even writing stories about my people for their own pleasure. After all, the two Kershu stories planned for #8 [of Masiform D] were both written by other people. HOWEVER, these are my invention, my Klingons, as is the art of Kershu fighting. (I'm the world's expert on it /modestly buffing her nails/. The only expert.) I really don't want anyone to publish stories about Kershu unless I have approved them. Legalities aside, I would HATE to suddenly find someone trying to marry Janet to Master Kinet. . . . 
From a post on one list by a fanwriter who wrote in several fandoms (Professionals, Star Trek: TOS, Star Trek: TNG, and Man from UNCLE) under three different pseuds:Some of you may be familiar with EPILOGUE, which is one of my TREK universes, which is a closed universe. That is, it is a complete novel in two volumes — eight chapters — and the eight chapters tell independent stories, with beginnings, middles and ends. But they are not really independent of one another, even though the first three appeared in TRISKELLION, way back in the early 1970’s. They don’t leave you satisfied, they leave you wanting the rest of the story, but it’s closed. There’s no more EPILOGUE. I will not write any more and no one else will write any more that in official EPILOGUE. You cannot prevent someone else from writing a story, but I will not recognize it—no matter how brilliant it is — as part of that universe because that one is complete... ... I was working off my own frustrations writing the first part of EPILOGUE. And then I came back and wrote part two after I had lived through and come to terms with that period of my life, and I had a book to complete. And then the artist goes on and finishes the story that was begun out of the emotion of a particular period. But it’s probably because it is so close to my own life that I don’t want anybody else fiddling around with it. It’s complete in itself. Now, that’s one kind of universe, where you as sole author, or perhaps with a collaborator write a particular thing, you finish it and that’s it. You don’t do any more. 
Please note that I do not give permission for sequels or rewrites of my stories published or to be published under the pseudonyms [A B], [S L] or [G K]. I realise I cannot stop anyone who wishes to do this, however, as I personally would find this distressing, I would hope anyone contemplating this action would abide by my wishes.
Differing Viewpoints: 1970s
General CommentsA fan, Catalenamara wrote:
Writing sequels to another person's story, authorized or not, was fairly common in Trek fandom in the early days. I wrote a piece that was published in a fanzine in the mid-70s. The next issue included two sequels based on my work.
I was:1. Startled. 2. Flattered, because I knew this was part of fannish tradition. 3. Honored, because it was nice that my work was well-received enough to inspire sequels. 4. Annoyed, as I really didn't care for one of the sequels at all. 
Example: "Variations on a Theme"
See the Star Trek series of stories, Variations on a Theme.From A 2007 Interview with Valerie Piacentini:
Often an idea came from another writer’s story; many of us wrote what we called “creative responses,” though it was considered courteous to ask the original writer’s permission first. I did once make a bad mistake, though. I wrote what was intended to be a short story based on Kraith, inspired by a version of Spock who appeared briefly. I didn’t ask permission, thinking it was too minor, but the short story grew into what became the Variations on a Theme series. (That’s another of my favourites, co-authored with Fiona, but as it’s gen, I didn’t include it.) Some years later I received a very gracious letter from Jacqueline Lichtenberg saying she would have allocated it an official Kraith number.
Example: "A la récherche de l'avenir" and "The Rack"personal statement was printed in Scuttlebutt #16 in 1979 by Bev Volker, April Valentine, Nancy Kippax regarding to an "unauthorized sequel" to their story The Rack:
In 1980, a fan named Mary Lou D commented on "The Rack's" authors' complaints:This letter is directed to the editor of the Canadian-based zine, Starbase M.T.L.. Last year, the zine published a story titled "A la Recherche de l'avenir' by Genevieve Lapierre... The word 'avenir' in the title refers to the ship Spock was offered in 'The Rack.' In our story, he turned down that command. However, in the 'Starbase M.T.L.' story, yet another inspired by 'The Rack,' Spock goes on to become the captain of the Avenir. That wouldn't be so bad. There have been other 'take-offs' done on 'The Rack.' having themes and content with which we disagreed. The difference is that the authors of these stories and editors who wanted to print them at least contacted the editors of Contact, wherein 'The Rack' was published, to receive permission. In this case, none of us was contacted. At AmeriCon '78, [the editor] proudly showed us the story, and we were rather upset. We requested that since the story was printed without permission, an apology appear in the next issue of 'M.T.L. saying he hadn't realized that an okay was necessary. He agreed. Now, the so-called apology has arrived. John states that the Lapierre story was submitted late but was too good to leave out of his zine and he didn't have time for the 'protocol' of writing to 'Contact's editors. His editorial goes on to say that since the character the story is built around, Val Kaminksy, played such a small part in 'The Rack,' he thought everything would be all right. John does mention that 'The Rack' authors were upset at the direction taken by the story, but emphatically states that he is apologizing for his 'failure to follow fannish etiquette and not for the content of the story.' Complimentary copies of his zine were given to us with the stated hope that all would now be settled. Well, it isn't. The problem may have arisen due to John's not asking for permission to print the story, but he seems to think that he would have received that permission. He would not have. First, the character of Val Kaminsky WAS of minor importance in 'The Rack,' but he was a character created by J. Emily Vance, and for that reason, NO ONE may develop him or give him a history EXCEPT J. Emily Vance. Secondly, the whole point of 'The Rack' was that Kirk and Spock were not lovers. In the Lapierre story, Spock is having an affair with Val Kaminsky, a gay who made a pass at him in 'The Rack.' Not only did Lapierre tamper with the Vance character, she tampered with Spock as postulated in 'The Rack.' Lapierre has made a mockery of the Kirk/Spock relationship in our zine -- indeed, in all of fan-fiction -- by stating that with Kirk dead, Spock would jump into another man. The third point, though, is the most serious. In the Lapierre story, there is a flashback scene in which the first meeting between Spock and Val is recalled. And there, lines of dialogue DIRECTLY FROM THE RACK HAVE BEEN USED. There is a simple word for this sort of thing. It is called plagiarism... Other creators of universes in fan fiction have been plagued by plagarism and the time for it to stop is NOW!" 
In 1980, Leslie Fish had this to say about "The Rack's" various sequels, authorized and not:And for something completely different! I was considerably amused to see in the final issue of "Scuttlebutt" an indignant denunciation by a set of zine editors, of another zine, which had appropriated a character from one of their stories—used and distorted that character! The complaining zine was one guilty of grossly distorting Mr. Roddenberry's characters, and failed to see the humor of the irony. Look at it as sensitivity training, girls—now you can understand how Gene Roddenberry must feel, and how fans feel when they buy your "Star Trek" zine and find it's nothing of the kind. Sweet revenge—and the bitter bit! 
In 2006, Catalenamara wrote:As for characters and situations written in fanzines, it's customary and considered good manners to ask the author's permission before writing variations on his/her theme, mainly because fan-lit is strictly nonprofit, and credit is all we have to give. No law requires this, and all that a law-court could give a plagiarized fan was a demand that the plagiarizer apologize in public. I'm not aware of the Scuttlebutt incident that ML Dodge refers to (I#28) but I've seen a similar case in an unauthorized sequel to a Contact story; what the annoyed original author did was write her own sequel, which was considerably better than the unauthorized sequel and which refuted it on every point of the plot. If the Scuttlebutt authors do the same, the Bad Guys will be refuted and fandom will benefit by an artful argument and a good story. 
TOS fandom reached something of a tipping point regarding unauthorized sequels after the publication of the death story “The Rack”. Sequels appeared, both authorized and unauthorized. The authors of the original story were so angered by the publication of the unauthorized sequel that they made quite an issue of it. After that point, as far as I recall, far fewer people wrote unauthorized sequels in TOS fandom. 
Differing Viewpoints: 1980s
General CommentsFrom a Star Wars letterzine in 1984:
From the author of a Star Trek: TOS zine:...familiarity is no reason to treat your fellow fan's work with anything but the respect it deserves. In such cases, it behooves the conscientious fan writer to search her memory carefully, to determine whether each part of her creation is: (a) made up by herself, (b) from the saga, or (c) part of another fan writer's universe. If the latter, The Protocol Droid proffers the following suggestion. Make up your own. Thus you will win plaudits for your originality and imagination, and not face the problem of utilizing another'screation. The galaxy "far, far away" offers limitless possibilities for such flights of fancy and, if you find yourself unequal to such imaginative work, The Protocol Droid respectfully suggests that perhaps creative writing is not your field. However, if you feel that another author's creation is just right for your universe and that no other will do (and such situations, The Protocol Droid admits, will occasionally occur), the proper behavior expected of civilized fans is as follows: Send a brief, polite note to said author, explaining what aspect of her/his universe you would like to use. (A few admiring remarks on the author's work would not come amiss at this point.) Having obtained this permission, you should insert an author's note to your story, giving credit to the original creator. This is not only good manners, but may protect the original creator's copyright, should she ever wish to use the creation in a professional story. Occasions will arise perhaps when all your caution will have been in vain. You unconsciously pick up another author's creation and use it...and before you realize your mistake, the story is printed. In such a case, The Protocol Droid suggests that you write the original author a brief, dignified letter, explaining your mistake and offering your apologies. 
I am planning a sequel [to Broken Images], but it may take awhile. It has to incubate while I meet other commitments. Several people have approached me or Vicky & Barbara about continuing the tale themselves. I am flattered by the interest, but please, no. That would make it impossible for me to do my own sequel, & I don't want to get involved in the kind of quality control Jacqueline Lichtenberg exercises over Kraith. It's just too costly in time & energy. 
Example: "Looking Glass Universe"
At the time the stories were written, many of the paper circuit stories contained no author name, so when Ellis Ward wrote her 'sequel' to Felicity M Parkinson's Looking Glass World, she had no idea who to contact to obtain permission. In the 1990s Ellis Ward explained that her two stories were not sequels per se, but more "inspired by" Looking Glass World. The original story by Felicity M Parkinson was a take on the Star Trek Mirror universe where the characters are unpleasant (as in the Star Trek Mirror 'verse) and gay (not in the original Star Trek Mirror 'verse.) In "And Memories Die I" Ellis wanted to explore what Doyle might experience when he finally remembered what he had done (and what had been done to him) in the mirror universe. In "And Memories Die II" she wondered might happen if the Mirror characters were to once again come into contact with 'our' Bodie and Doyle. Ellis later explained in a letterzine that Felicity M Parkinson was not pleased with the sequels as she (a) had not given permission and (b) would not have taken them in the direction that Ellis had chosen. In her letter, Ellis explained that as far as she was concerned Felicity M Parkinson's "is the only "authorized" version and should Parkinson ever write a sequel, it will be the "official" sequel. Ellis also apologized for failing to obtain permission.
Differing Viewpoints: 1990s
General CommentsFrom an X-Files fan:
From a Pros fan in 1991:Darned flattered [that my OFC, Jackie St. George, is used in other people's fiction]- as long as they ask permission! There was an unfortunate incident a few years ago when I tripped over a Babylon 5/XF crossover that started off with Jackie being a Ranger - and NO permission. The disclaimer stated flatly that the author didn't bother to even TRY to contact me, since he was sure I wouldn't mind. I did. One fast e-mail later and he pulled the story from all the archives along with a long apology. I hate laziness. One short email and I would have given permission gladly. 
From a Pros fan in 1991:I just feel that if I created a universe and someone else started writing in it, that wouldn't bother me. I'd just write something else if I didn't like the way they had done it — the official version. If something you write generates ideas and discussions (verbal or written) isn't that something good? I like for people to think about what I write even if it's only a little dumb humor. And if they feel compelled to write, what's the harm? 
From a Pros fan in 1991:On writing a sequel to someone else's story, or in someone else's timeline or "universe": the issues here, for me, are twofold. First, writers should get appropriate credit (or blame) for their creations; a sequel-writer should not seem to have originated what she adopted from someone else, and the original author should not be thought to have written the sequel if she didn't. Second, it should be clear to readers, especially in an on-going series or "universe", whether some stories are "not in the timeline," are less authoritative, than others. There's a third point which is that authors have a moral, even if not legal, interest in their creations. So I think that anyone wanting to circulate or publish a sequel to someone else's story has the obligation to ask that person's permission. The original author has the right to require a credit line: "'Morning Headache' by Phillippa Hepplethwaite, a sequel to 'Midnight Joy' by Cindy Candy." If the original author is planning a series, or if she doesn't agree with the way her characters were used, she can indicate this in the credit line with "an unofficial sequel," or "not in the 'Night and Day' series." She may need to see a copy of the sequel before deciding on the exact phrasing. Given these protections, it's hard for me to imagine circumstances which would entitle the original author to refuse permission to a would-be sequel-writer. If she does, however, then the second author can write it for fun and only show it to a few friends, or change it so that it no longer relies on the first story. It's rude for the first author to refuse permission when assured of proper crediting, but ruder for the second to publish the sequel anyway. In some cases, this doesn't apply. 
From a Pros fan, [H G], in 1991:I've been in fandom some years now and have literally hundreds of friends and/or contacts, many of whom have been writing at least half as long as I've been alive. I put the question about and the consensus has been so far universal with my own feelings on the subject. The words "plagiarism" and "stealing" were the less emotionally evocative ones used. "Why would they want to steal my universe?" "Why can't they create something of their own?" "I wish they'd plagiarise someone else." "I'd be very upset...." and so on in that vein. The exception was the one I mentioned last letter and that is if permission was asked beforehand from that universe's creator, as well as giving them final say as to whether the story sees print once it's finished in case the details go contrary to the creator's concepts or plans for further writing. Anything beyond that was greeted with extreme irritation and, if I must admit it, I would be horribly upset to be treated any different as well. 
From a Pros fan in 1991, this one tying legitimacy to origin:I've been interested by the debate regarding sequelling someone else's work. When it's happened to me I've taken it as a terrific compliment, as much for the fact someone else took my work seriously enough to think about it as for any other reason. I'm puzzled that anyone should get hot under the collar about the idea; we don't have a copyright on these guys, we just play with them (happy thought). As these days the majority of stories contain the author's name I don't see where the confusion could arise. Obviously, as Shoshanna suggests, in on-going universes a simple "inspired by" makes it plain that the story is outside mainframe — as, oh joy, Lois has done. Incidentally, I'm looking forward to reading the other vignettes (and Kate's comments). As for asking the original author's permission, no one ever asked mine, nor did it occur to me that they should have done. 
A discussion among X-Files fans in 1994:On the subject of should you do a sequel to someone else's story. I have a theory about that! I think it depends on the source of the story. If you read it in a zine, it is possible, through the zine editor, to locate the au thor. You should definitely do so before you put out a story set in that per son's universe. For the most part, if you identify the origin and state plain ly that it is a sequel not in the author's universe, the author will not mind. It is harder to write stories off the circuit. Often, the origin of the story is completely lost. Only half the time is there an author listed, a date is even more rare, and I have even read two that did not even have titles. Finding the author is harder here. People put stories into the circuit for different reasons than they put them into zines. Passing them around gives the author much more freedom to experiment, to show around only part of a story, to play with factors which might not be acceptable in a zine. It is less structured. At its best, it is very often one person's story, straight from the gut, flaws and all. A zine story has been filtered through at least one person: the editor. Very often this improves a story, at least in the granmar/typing/spelling areas. Some times an editor's typo or presentation, or late printing can harm a story. I know a fan who had parts two and three of a trilogy appear before part one because of an editor's problems. These things happen. If you want total control of your story's final form, though, it is best to pass them around. The stories sent out this way often get read more widely than those in zines. They go far and they go longer. But if it is in the pass-around format, it is in some ways more in the public domain than a zine-printed story, and it is more likely to have a sequel by someone not the author. Does anyone see this differently? At any rate, I think this is why older fans, who started with the zine-based fandom, might feel more strongly about somebody doing se quels to their work. 
From a Pros fan, [MS], in 1996:
Hi, everyone, I thought that my recent experience with "Bokor Holiday" might be a good enough reason to begin a little discussion about that dreaded topic, "Netiquette". Now that the .creative is enjoying a run of imput, perhaps some groundrules should be laid. My contribution: Please, ask before using material from other peoples' works! Any other good ones out there? Peggy -- Peggy Mei-Ling Li
- at the same time, it might be interesting if at least references to other creative works are allowed, so we can sorta intermingle all of them. For example, if Peggy writes a story about a giant six-headed octopus that impregnates Scully, then Joe Writer should be able to reference in his story about the love-making styles of six-headed octopi. -- Robert A. Hayden
- Re: asking before you refer to other people's works. Sounds fine to me. Patti and I asked Kellie (Gemma, Ancient Dreams) if we could refer to Gemma in our stories. Actually we discussed cross-referencing, that is, referring to incidents in each other's stories in order to create our own history and time line. Especially since so many of us wrote post-X-Files-shutdown stories. Anyhow, asking just sounds like common sense to me. However, we must be patient if oversights are made. This is a new medium, after all. ;-) Marisa DDEB Black Ops -- Marisa Golini
- Re: asking before you refer to other people's works. Very important! If Peggy is in the process of writing a sequel and has spent lots of time on it only to find that "Bokor Holiday" makes her sequel improbable, she has a right to be slightly pissed off. Lars --Lars Kremer 
From a fan, Shoshanna, in 1996:I much prefer a looser copyright concept, that enforces the ACKNOWLEDGEMENT of other authors rather than the EXCLUSIVE PROPERTY, even though I have publications - once the stuff is published it is by definition PUBLIC, and you have to let it go. I prefer having a bezillions sequels to Consequences around, rather than just having the one by the same author (the more the better); sure the sequels alter the perception of the original, but all our perceptions are colored by something, and all stories and stuff become part of the eternally whipped custard (NO PUN!8-) that is slash, and unites us all in this list. If i dont like a storyline, or a universe, I just forget about them: anyway MY custard is never yours, and reading is giving a personal interpretation that can have nothing to do with the author's, and neither is "more correct" than the other. So, it is very important to acknowledge and even contact the earlier author, since we are starting INTENTIONALLY from their ideas (diferent from using the canon's rules generically), but I dont think the earlier author should be proprietory about it....To sum up, gentlebeings, all this worry about 'mine' and 'yours' is kinda like "purity" -- let's forget about it and just have fun..."
From a Pros fan, [MS], in 1998:... if the first author refuses permission [when asked], then the would-be sequel writer needs to decide whether she's willing to have the first author hate her. Or, in more general terms, how big a stink she's willing to make: how much it matters to her to write that sequel in that way, and how she feels about the first author not wanting her to, and what it will do to her other friendships and general rep in fandom (and to the first author's, when the second tells all her friends the story of what happened), and so on. Ultimately it's a matter of a personal sense of ethics, and of practicalities; fandom (thank god) has no means of enforcing any one person's code of behavior. The best way to keep people from writing sequels to your work, since you clearly don't want them to, is to ask them not to -- publically when the topic comes up, as you have just done, and privately when people ask permission. They may do it anyway. Oh, well. If you go pro you can sue, and confiscate offending fan stories and pulp them, as Chelsea Quinn Yarbro did a few years ago. As a fan writer, all you can do is express how you feel, and hope for the best. 
From a Star Trek fan in 1999, answering another fan's question: "When is using something from another person's story taking advantage of 'fanon' and when is it plagiarism":[regarding asking prior permission]: I do have some manners... 8-) I would ask but I would expect a positive answer, with no fuss made. The difference between being in some relative stranger's living room and asking permission to get a drink ("please could I have a drink?" - "Help yourself" - "Are you sure I can open your fridge and take whatever?") and being at some relative's and bellowing, while I am already opening the fridge door, "Can I take a beer?" I am still asking, but it is the difference between begging the author to give written permission before I start writing, and putting in front of my story a note that goes "I used MarySue's scenario - thanks MarySue!" [and regarding the connection of stories with authors]: I might say that my stories are not my blood but my cut hairs on the floor of the hairdresser's - they WERE a part of me but they are gone, and it didn't even hurt. 
I guess I've been writing fan-fiction long enough to answer this question (does writing since '80 qualify me as having enough experience?). IMO it's not plagiarism if (1) if it was *not* done with a deliberate, conscious intent to steal something from someone else (IOW, malice aforethought), or if (2) you have that person's permission. If either of these conditions are present and somebody uses something I've done in one of my stories, I'm inclined to think along the lines of "imitation is the sincerest form of flattery" and feel complimented, whether we're talking "fanon" or anything else. (I have been known to give fan-writing friends permission to use specific things in their stories if they ask first, though I prefer to be credited somewhere in the margins or something as coming up with the idea.) As always, YMMV. 
Example: "Catharsis" and "Alternate Ending to Catharsis"
Example: "The Thousandth Man" and "No Bull"
Differing Viewpoints: 2000s
Example: "Take Clothes Off As Directed"
"Take Clothes Off As Directed" is a John Sheppard/Rodney McKay slash AU by Helen posted in 2006. Identified by the author as "an unauthorized homage," or without input or permission from the original author, "Take Clothes Off As Directed" was based on another AU story by Xanthe (Coming Home, a prequel to General & Dr Sheppard) that postulated an alternate universe in which sexuality was classified according to BDSM power dynamics, rather than gender. In Xanthe's stories, her alternate universe was a society where couples could achieve mystical soulbonds in their relationships. In contrast, Helen used the top/sub power dynamic as the basis for an allegory on gender roles and sexism in modern society.
Xanthe' reaction: While Xanthe herself has never mentioned Helen's story publicly, she has referred to Coming Home as "the story the SGA Big Name Fans all got their knickers in a twist about" and stated that events surrounding it resulted in "a kind of bonkers and yet deeply nasty hysteria that made me reassess my involvement in fandom". 
See Take Clothes Off As Directed for more.
Example: "Phantom Pain"From a fan in 2007, an outraged comment which generated forty-three responses about a fan's remix of the Sentinel story Phantom Pain:
A response to the above post:HOLY SHIT BATMAN!
Okay, okay, I need to breathe. I need to calm down. I need to ... need to....
...get a life.
SOMEONE just posted an ALTERNATE ending to ANOTHER author's story WITHOUT permission and to add injury to insult - explained that the reason for her posting an alternate ending was that she didn't LIKE the original author's story!!!
If anyone did that to me - I'd be spitting nails. And yes, I wrote to the author - but I did so in "This is just me..." way but damn it, this is NOT kosher and don't YOU DARE bring up the whole "but we write fanfiction and change endings and add missing scenes all the time" argument because no matter what you say - it's NOT the same. Not even remotely.
Why not, you ask? This is why:
Taking a piece of fanfiction by one author, and changing it because you didn't like the ending and then posting it - without PERMISSION - is the same as if ABC decided they didn't like the way CBS ended M.A.S.H. so they redid it their way and televised it. It's NOT done. Because it's not right. It's a line that not even television is willing to cross and we have similar lines in fandoms - as well we should.
Television is one medium - we're another.
And it's JUST WRONG! ::huffs a bit of hair off her face::::calming down now:: 
Another comment:That is soooo wrong.
It's like stealing someone else's work.
You do your own stuff. Period.
If you don't like the ending, oh well. If you want a different ending, don't post it if you re-write it. I wouldn't even re-write it. Just think it.Wrong. Soooo wrong. 
Another comment:I actually felt the same dissatisfaction with April's story as the writer of this "sequel." I may even have mentioned my dissatisfaction to April -- it's been so long I don't quite remember if I did or not. I do remember that April was the kind of person one could have a civil conversation with about both what you liked *and* disliked about her stories.
And I do often find myself reading other people's stories and thinking I like them, but I'd do this or that differently. A few times, I've asked for, and gotten permission to, do a "remix." Other times, I've managed to turn my story into a take on the same general theme, with little or no obvious connection to the story that provoked mine.In fanfic, we are inspired by each others' stories as much as by the "canon" source material. I feel this is a fact that needs to be openly acknowledged. But we can take inspiration from each other without stepping on other people's toes. It just takes a little thought, and as others have already pointed out, courtesy. 
Another comment:Then I wonder why she hadn't noticed that this was hardly common practice, you know? Ignorance is understandable but even in the fuzzy world of fandom, you get a gist of how things work. If she still believes she did nothing wrong, I wonder if this is going to happen more often if people find themselves dissatisfied with a story. 
This comment is from the fan who wrote the offending story:How pathetic is it that I don't find it surprising?? What a sense of entitlement! I might think to myself when I read a fic, oh I'd have ended it this way or think I might have written a scene differently but I would NEVER write another ending! At least not write it and post it without ever talking to the author! Audacity--I don't use that word very often but man oh man does it fit in this case! 
This comment is from the author of the original story, April Valentine:I never meant any harm, nor did I think I had inflicted any at the time. By admitting to not having April's permission and stating that I'd remove the fic if she asked me to, I didn't mean that I thought I'd done something wrong. But I took my own opinion/attitude as basis and that was wrong, not to mention thoughtless/careless/stupid because the risk of offending her (and others obviously) was entirely too great.... As to why I posted my "Alternate Ending", I guess I felt strongly about it and wanted to share it. That was a narcissistic thing to do and I am truly sorry. I do want to state though, that I definitely meant no disrespect to story and still don't , even if you are entitled to not believing me. 
I found out from a friend that the "alternate ending" story had been posted, however…. didn't go online last night to read the story. My friend was worried that [I might be stressed] by the posting of this story -- however, people have taken it upon themselves to write alternate endings to other stories I've written in years past in Trek fandom without permission  so it wasn't like it was something unheard of …..I'd've preferred to be at least asked if it was okay for the author to play in my universe first, but she did apparently credit me with having written the story that inspired hers and said it was a good story and well-written, etc.
So I'm fine... would like to read it just to see someone else's take but again, yes, it would be polite to ask the original author if it was okay to write and post something based on her work... we all write in someone else's universe without asking permission -- those who foolishly have asked have been treated to cease and desist orders for their trouble. But as several folks have pointed out, it's just common courtesy to ask permission from a fellow fanfiction writer. The author just obviously didn't know to do this, no big deal. While I appreciate the comments that say she didn't get the satisfaction of thinking up the whole plot, yeah, we all derive our ideas from the series and yet get satisfaction as writers despite not being completely original.
Still, with the onset of the lj world, fandom is much less a community than it was before. There have always been those that wished to make it a community and feel that bond with others who love the same shows and who are by nature polite and thoughtful while others have gone their own route and in the absense of written rules and regs, didn't bother with such niceties as asking permission or even giving a heads up to someone who might get their feathers ruffled by something they've done.…. Anyway, imitation, or in this case, continuation, is the sincerest form of flattery and I'm glad that someone was moved enough by something I wrote to write something in the same universe.” 
Differing Viewpoints: 2010s
General CommentsFrom a A 2010 Interview with Brenda Antrim:
From A 2010 Interview with Angelfish:I do it all the time, only the writers I'm rewriting get paid for their stories... I don't care if someone wants to write a story based on something I've written. I'd like it if they told me, because I'd be interested in seeing what ideas they came up with from what they read. I DO care if they copy wholesale from my story and stick it in theirs -- that's not rewriting, that's plagiarism, and it pisses me off. That's happened a few times, and I've registered complaints with archives and had the stories removed. But using my story as a springboard? Hey, go ahead, dive in. The one time I wrote a sequel to another person's story (in X Files), I did ask for permission beforehand. Just like when I wanted to scan a fan art piece, I called the artist and asked for permission. It's only polite.
From A 2010 Interview with Helen Raven:Goodness! I've never had that happen -- not as far as I'm aware, anyway. I don't think I'd mind. It would be a compliment, I suppose, provided they didn't simply find your own ending so godawful they felt overpoweringly compelled to rewrite it.
From A 2010 Interview with Tarot:I'm the last person who could get snotty about this, since I've done it three times (twice with permission and once without). If someone did it to me I'd probably feel both flattered and apprehensive, and would need to remind myself at least once that I have no right at all to attempt to control how people react to my work once I release it -- as long as they don't try to present my work as their own. I'd probably be cautious about reading the story, and would ask friends who had read it whether or not I should risk it. I think it would have the potential to be upsetting and to take over my thoughts for days, and I'm under no obligation to open myself up to that -- just as the other writer would be under no obligation to refrain from writing her story just because I might not be thrilled with it.
From A 2010 Interview with The Hag:I have no problems with either *g*. Hey, it would be the height of hypocrisy to be against it, wouldn't it, given the very nature of fanfic?
From A 2011 Interview with Meg Lewtan:Mostly I think I'd hate it, but it's difficult to say in the abstract.
From a Professionals fan, Sebastian, in 2014:It never bothered me for the simple reason, I was already writing sequels to other peoples' work. As I said, I have two K/S stories that are sequels but I did ask the zine editors who published them if they thought the authors would mind. In both instances, I was told that those writers had no objections to my stories.
However, the foundation of the vast majority of fan writing is the series themselves. In writing fan stories, everyone who does it is writing sequels. In borrowing the characters, they are using other people's work constantly without their permission.So given this statement, who am I to say what other people can and can't write? As I've borrowed plots and written sequels myself, I can't say what people can and can't write and refusing permission is useless, because it's physically impossible to stop them.
From 2015 comments by copperbadge:...they were not our characters to start with, it is all very unofficial and depends a lot on goodwill to share and respond and feedback. I would never presume to own 'my' characters - even if I didn't like the direction a story inspired by one of mine had taken (which I don't think has ever happened as it goes.)
We began writing fanfic because we saw a pair of humans onscreen, a situation and we wondered what if. We wanted, we hungered for, more. It isn't surprising at all that sometimes we read a story and want that more and feel that what if all over again.I have had good experiences with people sequelling my stories. Helen Raven - who could object to HR carrying on one's created universe - her talent surpassed mine and then some. 
From mikes-grrl in 2015:The question of who owns an idea is a deep one, which is why this discussion gets tricky fast. But remixing the work of someone who is living, without their permission to do so, is generally frowned upon because we believe this infringes on their right to earn off their work, be that money (as in the workplace) or social capital (as in fandom and to some extent in academia). An exception is if you’re making a specific statement about their work, in which case you’re usually saying “Come at me, bro” and it’s understood you’re still not taking credit for someone else’s idea. Sometimes it’s a glorification thing, like with Warhol’s obsession with commercial graphic design and popular imagery. In both cases, the original work being remixed is generally so recognizable that everyone knows it’s a remix and it’s therefore a statement rather than a theft. Usually the remixing of a popular property in a critical way is confined to aggressive protest where you can generally look at the original property and say “Yeah, they had that coming.”
Fandom straddles a line, however, because we often remix the original canon out of love for it, or out of a frustrated sense of “I love this story but THIS ONE PART MAKES ME CRAZY CAN WE FIX IT”. We remix to queer canon, to racebend and genderbend, to save the life of a character, to fix a perceived injustice, to put our heroes into lives more like ours, or just to see “what would happen if we changed this one thing?” So if we can do it to canon, why can’t we do it to each other? Well, mainly because our remixing of canon is a Warhol glorification — everyone knows the foundation idea isn’t ours, and that we’re playing in the sandbox, not charging admission to it. If you remix a fanfic, people won’t necessarily know the idea wasn’t yours — and if you link to what you remixed without asking, you may come off less “I love your fic like Warhol loves soup labels” and more “I think your fanfic wasn’t good enough and I don’t care enough about you as an individual to ask first before I fix it.” Which is why you ask. More communication is better than less, and if you ask, the writer knows that you love their idea, rather than hating their execution. And it means if they say no, and you respect that, you’re not humiliating them in public by implying you think their work was inadequate.Asking permission to Do A Thing in fandom is a way of making sure people don’t get hurt. The creators of our canon have power we don’t; their message is disseminated to a much vaster audience and they’re paid for it. The creator of a fanwork that someone wants to remix doesn’t have that power, and they’re an equal, so if you remix without asking you’re taking a shot across the bow with a cannon, not throwing pebbles at a window. 
A recent kerfluffle in a couple of RP sites made me realize that one very important aspect missing from a lot of fandom participation is that the rules of “transformative fiction” apply universally.
That is, if you riff on a show or movie by creating fanfic or fanart or RP blogs without permission (which, uh, is exactly what we all do), then you’re not exactly in a position to bitch when someone does the same to YOUR work.
But hypocrisy tends to run rampant. BNFs ax requests by their fans to be able to riff on their own fanfiction – “It’s mine and that makes me uncomfortable.” RP blog admins get in cat fights over ideas being “stolen” from each other. Community founders freak the fuck out when someone takes a character in a direction “not sanctioned” by them (~moment of silence for the Great Clan Mitchell Fiasco~).
The common defense here is that fandom is some kind of “community” with shared values. That a cohesive community with shared values exists perhaps could be said of some small fandoms (when I was in Life on Mars-UK on livejournal, that was certainly the case) but in larger fandoms that’s just ridiculous. The numbers are against you: there will the factions, and wank, and a lot of disagreement about everything.
There is only one universal, shared feature to our so-called fanfic/fanart community: that every single thing we create – art, stories, blogs, costumes, jewelry – is a transformation of copyrighted material owned by someone else. If that idea bothers you on a personal level, then maybe you need to think carefully about what exactly you think you are doing here in the first place.My point is that we can’t expect people to respect rules of ownership in a “community” (fanfiction/fanart) based on breaking those very rules. Screaming out “they stole my idea!” in THIS space is not just hypocrisy, and it’s not just kind of silly, but it’s actually a complete refutation of the whole reason we’re doing what we do in the first place. 
Different Attitudes in Different Fandoms/Different Times: A 2006 Discussion Among Pros Fans
In 2006, there was some discussion among Professionals fans about different fandoms and expectations regarding unauthorized sequels:
I was just talking about [unauthorized sequels] with a friend during and after the SGA fuss that broke out recently.  Pros is a very different fandom from SGA - thank all the graces!
It was interesting to me that in reading the various LJ posts, both those focused narrowly on the SGA fandom and those who broadened the question to other fandoms, that the overwhelming majority of those upset by the idea were relative newcomers to fandom. And by relative newcomers, I mean post-Internet fandom participants. I think the idea that permission should or even must be sought and received before writing a story sparked by another fan fiction is very much an Internet-fandom related question. I found it extremely interesting that several of the posters who offerred a different, historical viewpoint had experience in writing Pros (e.g. Sandy, Cynthia, Nansi...
Pros has a long, long tradition of writers sparking off each other's work and writing stories that are inspired by and/or negative reactions to other stories, both with and without seeking the approval from the writer of the source inspiration. I'd even say that was one of the major forces that propelled and shaped The Circuit. Some stories are actually sequels while others are more loosely inspired by a plot point, image, or question. Some sequels have been authorized (e.g. Joana Dey's story, Life Goes On which is an authorized sequel to Kathy Keegan's Gentle on My Mind series), and many others have not...There are many factors that I think shaped the attitudes in Pros, amongst them its development as a slash fandom that grew out of The Circuit (whose unique influence cannot be over-estimated), its huge zine base, and that it was well established before the Internet and online fandom came into being. Any of which is rich enough fodder for a dissertation-length response, though I'll spare you that for the moment. *g*... 
I don't follow SGA or ST (or in fact any other fandom!) at all, but it was interesting to hear their aspect of the debate - thanks! And your thoughts about internet vs zine/circuit viewpoints sound very plausible to me (with clearly exceptions on all sides!) I wonder if the accessibility of everything on the internet, and its notoreity for enabling people to "steal" from each other - in general not just in fandom I mean, plagiarising sites for homework, downloading information in exams, stealing bandwidth, for example - might make people a bit more leery. Whereas writing a sequel that was perhaps likely to be seen by fewer people via zines etc limited the damage on its own, if the author didn't like it for whatever reason, now that "damage" is much more easily widespread and available... And so people are more defensive about it to start with? 
I'd add in Star Trek-TOS as another fandom in which such a question (is permission expected or necessary) would have been looked at with bemusement during most of its thirty year history. A nod towards acknowledging the inspiration, yes, absolutely, but permission? That's a very different thing.
As to whether or not Pros fen today would view an author writing a sequel to a Pros story written by another author as a breach of etiquette? I'd say that it would be much less likely than in many other fandoms - and in my opinion that's a very good thing - but it would be variable. Different fandoms can have very different norms, and one's prior experience in a fandom often shape their future expectations in other fandoms. So it would also depend on how recently the person asked came to Pros fandom, if Pros was their first fandom, and if they had any sense of Pros unique fandom history.
And too, I think opinions will vary on whether the story is a true sequel (i.e. that it accepts the prior story as "canon background" if you will and builds off it) or if the new story is sparked by the prior story, but doesn't use it as "canon background" - instead moving in a different direction.Oh, and a last thought (at least for this post *g*) - not all the sequels or stories inspired by others in Pros have been complimentary. Many of the follow-ups to Consequences were attempts to repudiate or remodel the original. There are also several instances where follow-up stories were taking the piss regarding the originals  
That was really what started me thinking about it actually - people so clearly did write the sequels in the past, and yet I had a sort of inkling that it was a bit frowned upon these days...
I think that inkling isn't entirely wrong; there are those who don't approve as you saw on the list. And no, there aren't "blanket rules" but I still think the dominant paradigm remains that being inspired by, riffing on, and even writing sequels for other's stories is an essential - and valued - component of Pros fandom.I also think that you'll get different gradiations of support for that view depending on if you speak mainly to readers or readers/writers. And don't forget to add in the human tendency to make exceptions for our own actions while calling others to account - no matter what the issue. 
You can easily while away an afternoon just browsing through the SGA fuss, but I think it's particularly illuminating when you read some of the related posts as the debate moved out to wider fandom circles. I find it interesting to see how many people had not a clue about larger fandom history, or even that norms could - and do - vary widely across different fandoms.
Whereas writing a sequel that was perhaps likely to be seen by fewer people via zines etc limited the damage on its own, if the author didn't like it for whatever reason, now that "damage" is much more easily widespread and available... And so people are more defensive about it to start with?
I don't know. I think it might be part of it, but I think it has more to do with how people view fandom itself. Is fandom (either broadly speaking or restricted to your own specific fandom) a place where communal discussions and other fen interactions lead to creative expression, and the communal/interactive inspiration is expected, accepted, and important? Or is fandom a forum where you, as an individual, seek an audience for your proprietary creative expression?Before the Internet, I would argue that stories inspired by other work or those written in reaction to other work (riffs, missing scenes, repudiations, even sequels) were another way to have fannish discussions about various issues. Yes, there were also LOCs, and reviews, individual contacts (in person, by phone, and/or by letter), and panel discussions at cons. But the stories themselves acted as powerful venues for such discussion - especially in Pros. Today, there is paradoxically both more discussion (in absolute volume) and less willingness to have discussion (proportionally).... 
Before the Internet, I would argue that stories inspired by other work or those written in reaction to other work (riffs, missing scenes, repudiations, even sequels) were another way to have fannish discussions about various issues.
Yes, absolutely. This sort of fannish conversation - "debate by fic", as it were - has always been something I've enjoyed.I've often talked with people who are frothing mad about some story they've read. My suggestion is always (if they're writers) to write a story which expresses their own viewpoints. It doesn't have to have anything whatsoever to do with the original piece. Just decide on your points of disagreement, and write your own story as a way of exploring your own thoughts on characterization, etc. 
Changes in Attitudes Over Time
Less strict? More strict?
Different Attitudes in Different Mediums
Here’s what I recall. I believe the panel was titled something like “Ownership in Fandom”.
There were two main topics covered. The first concerned vids, and vidders taking footage from other people’s vids and re-using it. I’m not familiar with the technology involved in making vids. I was aware that many vidders clearly do alter their vids in some ways, via color changes, effects, and speed changes. I hadn’t been aware, until this panel, that some people take this sort of altered footage from other people’s vids and incorporate it into their own work.
The second topic was, is it ever appropriate to write a sequel to someone else’s work? And, is it appropriate to use someone else’s original characters in a new work?
Someone immediately introduced the question - if it's OK for fan fic writers to use someone else's universe in the first place, why is it not OK for fan fic writers to use another fannish work as their jumping off point.
People were divided on virtually every point brought up during the course of the panel.
People responded with their personal experiences – I believe it was primarily people who had had sequels written in response to work of their own. Some had given permission, some had not. Some were fine with this, and some were furious.Examples from fannish history were introduced. 
- Eridani Triad #1 (1970) contains a trilogy of plays by Doris Beetem set in Ancient Vulcan in the time of Surak. The introduction to this trio: "The following story is an unauthorized sequel to Jean Lorrah's "Parted From Me," which appeared in Triskelion No. 3."
- A la récherche de l'avenir (1978) was a responsefic to The Rack, and was a story that caused great controversy.
- Letting Go Is The Hardest Part and Lovers In A Dangerous Time are sequels to Devil Angel, a Hanson and The Moffatts fic. Fans were encouraged by the author to write their own "lost chapters" and many fans wrote sequels when the original story was abandoned.
- The Silent One, an unauthorized sequel to Hanson fic The Quiet One.
- Take Clothes Off As Directed, a SGA example
- see more of her comments at Media Fandom Oral History Project Interview with Ruth Berman
- from Cold Fish and Stale Chips #10 (1991)
- The fact that the 'Nu Ormenel' series was based on Klingons, someone else's copyrighted idea, seemed to have escaped these two fans' attention.
- from a personal statement in Scuttlebutt #7 (1978)
- from Universes in Science Fiction #1, the editorial by Anji Valenza
- from Interstat #12
- from Masiform D #7
- from a transcript of a writers' panel, published in Wulfstone, see complete transcript here, accessed March 6, 2013
- 2006 comments at CI5; Webcite
- Scuttlebutt #16 contains a personal statement from the authors. Boldly Writing says it was "a statement from the editors of the fanzine Contact, who were upset that someone had written an unauthorized sequel to their story, The Rack... No one I know of, however, remembers this unauthorized sequel.
- from Interstat #28 (February 1980)
- from Interstat #30
- 2006 comments at CI5 during a discussion about unauthorized sequels and Out of the Blue; Webcite
- from Jundland, Too #1
- from Not Tonight, Spock! Interview with Beverly Sutherland; Beverly's sequel was never completed
- Source: Morgan Dawn's personal notes, accessed June 6, 2013.
- from Working Stiffs Interview with Sheryl Nantus aka Sheryl Martin
- from Cold Fish and Stale Chips #9 (1991)
- from Cold Fish and Stale Chips #10
- from Cold Fish and Stale Chips #10
- from Cold Fish and Stale Chips #11
- from Cold Fish and Stale Chips #11
- alt.tv.x-files.creative › Creative writers... July 1994
- comment in the " Writing sequels (LONG)" thread posted to the Virgule-L mailing list on Sept 27, 1996, quoted with permission.
- comments on Virgule-L, quoted with permission (September 27, 1996)
- posted February 5, 1998, to CI5 Mailing List, used with permission
- comments by Gamin Davis, November 1999 at alt.startrek.creative.erotica.moderated
- Xanthe, Site Updates, February 9th, 2008, (Accessed 12 October, 2008)
- from Alyburn's Live Journal/WebCite, posted January 23,2007, accessed March 26, 2013
- comment by ninja007, January 24, 2007
- comment by nightspring, January 24, 2007
- veronicaluv. comment, January 24, 2007
- comment by babssg1, January 24, 2007
- She lists it as one of her favorite Sentinel stories here.
- comment by earth2skye, January 24, 2007
- One example is A la récherche de l'avenir, a sequel to The Rack.
- posted to Prospect-L by April Valentine on January 30, 2007, quoted with permission
- posted at Hard Facts, 2014
- The Sundry Times, So, as a long-time lurker in fandom, but not..., Archived version, a Tumblr ask and a response by copperbadge (March 2015)
- untitled Tumblr post,
- Probably regarding Take Clothes Off As Directed.
- 2006 comments at CI5; Webcite
- 2006 comments at CI5; Webcite
- See Two-Up Truly Queered, some more friendly than others.
- 2006 comments at CI5; Webcite
- 2006 comments at CI5; Webcite
- 2006 comments at CI5; Webcite
- 2006 comments at CI5; Webcite
- 2006 comments at CI5; Webcite