This began as a reply to Charles Yallowitz’s “Fairy Tale Rewriting Vs Fan Fiction”, but then it grew out of control and rather than dump it on his page I thought I’d post it here.
The question of rights-holders matters a lot to publisher’s lawyers, but I don’t think it’s as important to writers.
There are a lot of ways in which a writer can use another writer’s work as the basis of her or his work. What I would call Pure Fan Fiction is at one end of a continuum–where the characters, settings, and major events are all taken from a particular source.
There are degrees of purity in the fan fiction community, and a bewildering code of abbreviations to distinguish between different alternative worlds. There are fan fics in which characters who have died in the “official” world are still alive. There are fan fics in which a character’s gender or species have been changed.
There are fan created characters who have been written into existing worlds and then become part of an alternative canon. (And there have been cases where the original author has taken over a fan created character and written it into the official world–more fun for publisher’s lawyers.)
Then there are Cross-overs. Fan fiction has been written combining characters from a popular television series with characters from a popular series of books. (What if Dexter Morgan had gone to Hogwarts? Wouldn’t that have made things much more interesting for Harry?)
The question of how much change from the original source material makes a work no longer fan fiction has been in the news lately, with Fifty Shades Of Grey being described as a Twilight fan fiction, only without the supernatural elements and the supporting characters and a different setting and huge amounts of money for the male lead, and different names for everybody. I haven’t read Fifty Shades, so I can’t really comment.
I have read Cassandra Claire’s Mortal Instruments series, however, and I don’t see any resemblance to Harry Potter at all, despite the claims that it began as a Harry Potter fan fiction. Claire has so altered the characters and the world that it never occurred to me that one could be inspired by the other.
Genres are largely influenced by a particular work. One could make the case that Mickey Spillane’s Mike Hammer was Phillip Marlowe fan fiction. As Charles points out, J R R Tolkien’s Lord Of The Rings series has inspired the entire genre of Epic Fantasy.
I use a great many concepts developed by other writers in my own work. (Fortunately, I draw on sources that almost nobody has read, so I’m not likely to be caught. Unfortunately, I tend to admit that I borrow extensively, so that kind of negates it.) The semi-human races I call Ambimorphs and Blue Metal Boys are lifted directly from William Burroughs’ Nova Express and the Necroidim from Cannibal Hearts are my own version of Clive Barker’s Cenobites. The characteristics of the Outsiders are heavily based on C S Lewis’s Eldila, and one of my characters uses that word to describe them.
Other influences are less direct. Cannibal Hearts draws largely on the structure of Phillip Dick’s A Maze Of Death, but without any one-to-one correspondence, it is the pattern of escalation of events that I took from Dick’s work.
I draw on a lot of works published as non-fiction as well. I am a big fan of fringe/psuedo-science, and that shows up in the cosmology of my works. Charles Fort and Wilhelm Reich both heavily influenced the “how” of the Outsiders. (The “accumulator” that shows up in Cannibal Hearts is a direct homage to Reich.)
I don’t think that any author can be entirely free of the influence of other authors–what we read becomes a part of the experience that we draw upon to create our own work. The extent to which we are influenced by any one particular work is a matter of personal taste, however. I, myself, probably couldn’t write fan fiction that would be acceptable to the established fan fiction community–I wouldn’t want to limit my options to those in only one existing world.