The trilogy currently sitting atop the New York Times bestseller list is in many ways a fascinating one, the sort of Cinderella story that gives journalists a chance to make wild guesses about the future of publishing. E L James’ Fifty Shades of Grey and its sequels began on the Internet, evolved into e-books, were printed by a small Australian press, and, just a few weeks ago, were finally picked up by a traditional big publisher, Vintage, which paid seven figures at auction for the North American rights. It wasn’t a risky bet; the biggest trouble has reportedly been keeping physical copies on the shelves.

The book is notable, too, because to some degree, it’s forced erotica into the mainstream conversation. Much of the coverage of Fifty Shades of Grey has focused on sex: women are passing around the novels at spin classes and telling the Times how nice it is to be able to read porn and talk about it with friends. (“It’s relighting a fire under a lot of marriages,” one woman said.) But then there are the books’ origins: the trilogy started on FanFiction.net, as a story entitled “Master of the Universe,” in which James’ main characters, Anastasia Steele and Christian Grey, were called Bella Swan and Edward Cullen. It was Twilight AU, or Alternate Universe fan fiction, wherein Stephenie Meyer’s innocent girl and vampire were re-imagined as innocent girl and manipulative billionaire. The story eventually morphed into something more original — and “Masters of the Universe” was removed from the web — but the threads remained. “The book emerged from the steamy land of fan fiction,” said Jason Boog, discussing the legal and ethical questions for NPR. “Fifty Shades of Grey has opened the box underneath Pandora’s bed, and we need to decide what to do with the sexy publishing trend hidden inside.”

Why, when discussing fan fiction, do journalists often sound like anthropologists discovering some long-lost tribe — and a somewhat unsavory and oversexed one at that? To be fair, Fifty Shades of Grey is an erotic novel, but it represents a mere fraction of this “steamy land.” Let me take a crack at it: fan fiction is original work with largely unoriginal foundations, in which writers take established fictional worlds and spin them into something else entirely. Outside of all of the various fandoms, and even occasionally within them, a few assumptions seem to prevail: that there is something inherently embarrassing about fan fiction, that it’s cause for anonymity and secrecy, and that it is overwhelmingly pornographic — and often seriously, creepily pornographic. There’s plenty of that stuff, sure, but then, there’s plenty of original erotica out there, too. It’s all a sliver of something much larger. For every story that puts Harry, Ron, and Hermione in some kind of BDSM threesome, there are a thousand stories in which they manage to save the world without having any sex at all.

The literary establishment seems divided on the subject — those who even notice fan fiction, at least. (It’s here that we can part ways with Fifty Shades of Grey, which, as a romance novel, doesn’t really fall under the purview of the “literary establishment” — and the blurry dividers between genres are a wholly different discussion.) Writing for TIME last year, Lev Grossman mercifully skipped the baffled anthropologist shtick: the piece was clearly the work of a super-fan, and he laid out the basics with a great deal of affection. Fan fiction is “still the cultural equivalent of dark matter,” he writes. “It’s largely invisible to the mainstream, but at the same time, it’s unbelievably massive.” (FanFiction.net, the largest fanfic site in the world, has more than two million users and nearly 600,000 Harry Potter stories.) Grossman continues:

Fan fiction is what literature might look like if it were reinvented from scratch after a nuclear apocalypse by a band of brilliant pop-culture junkies trapped in a sealed bunker. They don’t do it for money. That’s not what it’s about. The writers write it and put it up online just for the satisfaction. They’re fans, but they’re not silent, couchbound consumers of media. The culture talks to them, and they talk back to the culture in its own language.

Some authors seem to love the conversation, but some, for legal or creative reasons, seriously hate it. Grossman highlights a few of its vehement detractors, like Orson Scott Card, Anne Rice, and George R. R. Martin, who says on his website that, “Every writer needs to learn to create his own characters, worlds, and settings. Using someone else’s world is the lazy way out.”

But writers have been lifting and borrowing and refashioning characters, worlds, and settings since people began putting stories down on the page. Grossman draws a line between literary influences, allusions, and homage and the world of fan fiction: he highlights 1966, the year in which Star Trek premiered and Trekkies were, in turn, born, and in which two great literary heists were published: Jean Rhys’ Wide Sargasso Sea and Tom Stoppard’s Rosencrantz and Guildenstern Are Dead. The latter pair were “written for profit, and they’re adorned with the trappings of cultural prestige; true fan fiction has naught to do with either one.”

I’m just not sure we need the distinction — and I’m not sure that it helps. Nearly every work of fan fiction on the Internet is accompanied by a disclaimer, some variation on “This story was not written for profit, and these characters are not my own.” But it’s copyright law at the heart of that, and to suggest that these writers have no interest in “the trappings of cultural prestige” creates a stark division between fan fiction and its literary counterparts. I have a deep respect for the devotion of fans, and I can certainly understand why one would write a story for love rather than for money. But it’s a multi-faceted world: many of these writers just want a different — and sometimes, a better — way into a story. Hasn’t literature has been doing that for centuries?

There’s fan fiction lore surrounding King Arthur and Don Quixote, but we find easier analogies with modern-day fan culture say, a few hundred years ago, when the novel as we know it was born. Copyright laws had been on the books since the seventeenth century, but the most successful eighteenth and nineteenth century writers watched helplessly as their characters were baldly lifted and reworked into sequels or just plain rewrites — and then sold to the public at a fraction of the price. Charles Dickens, already a victim of intellectual pirating across the Atlantic, watched domestic copycats put out seriously poor imitations of his books with dismay: “I have not the least doubt that these Vagabonds can be stopped,” he wrote. “They must be.”

This was pure plagiarism, meant to harm and to generate profit, not to elevate Dickens’s words. But a century earlier, Samuel Richardson found Clarissa, which he was publishing in installments, to be the subject of positive and somewhat extraordinary fannish speculation. Two sisters, Lady Bradshaigh and Lady Echlin, exchanged dozens of letters with Richardson, urging him to change the course of the novel (basically, they wanted to cut out the rape and death). In The Oxford Encyclopedia of British Literature, Carol Houlihan Flynn writes of Bradshaigh contacting Richardson: “Assiduously scribbling over the margins of all the volumes of the novel, she first writes him after finishing volume 4, cajoling, flirting, excoriating, loving, hating, but always admiring her torturer.” Her sister took things further: “Lady Echlin…seems more professional in her investment into the passions of Clarissa, and literally rewrites the novel…Richardson received and of course rejected her alternative ending, but they debated the critical differences in at least forty letters.”

The nineteenth century saw fans skipping correspondence with recalcitrant authors and writing their own endings for books that they loved, including the novels of Jane Austen, Lewis Carroll, and, most notably, Arthur Conan Doyle, who made the mistake of killing off Sherlock Holmes and whipping the detective’s admirers into a frenzy. The practice continued through the first half of the twentieth century, until the 1960s, when the term “fan fiction” was coined and the literary tradition merged with our current ideas of fandom — science fiction, “cult” television shows, terms like “continuity” and “canon” gaining significance in the process. As the Internet became pervasive, fan fiction communities grew and spread exponentially.

But the past half-century also played host to a lot of self-conscious borrowing and refashioning across literature: authors began to look for silences in the canon and probed the neglected perspectives they found there. Some post-colonial literature could easily be categorized as fan fiction. The most famous of these is Wide Sargasso Sea by Jean Rhys, which follows Jane Eyre’s “madwoman in the attic” all the way back to the Caribbean. Aimé Césaire’s Une Tempête draws the colonial themes out of The Tempest with an essentially direct re-writing of the play. J. M. Coetzee’s Foe exists within the confines of Robinson Crusoe, placing another character on the island with Crusoe and Friday, and explores ideas of authorial voice in the colonial narrative.

Outside post-colonialism, dozens of books fall within the realm of “parallel novels,” many of which take minor characters and expand their worlds. Peter Carey’s Jack Maggs emerges from Great Expectations; Geraldine Brooks looks for the absent father of Little Women in March. Michael Cunningham’s The Hours offers us two subgenres of fan fiction: the AU of the modern-day Clarissa, Richard, and Sally, and the RPF — that’s Real Person Fic — of the Virginia Woolf passages. With RPF, you’re not writing about Aragorn and Legolas’ lost adventures anymore — it’s Viggo and Orlando on the set, and who knew they might be an item? Every biopic that takes factual liberties could be classified as such, and the same could be said for plenty of books, from Colm Tóibín’s The Master (Henry James) to Ron Hansen’s Exiles (Gerard Manley Hopkins) to Julian Barnes’ Arthur & George (our old favorite, Arthur Conan Doyle).

So what’s the difference? Isn’t all of this just a bunch of variations on the same theme? Why does fan fiction’s stigma persist — and why are remixes and mash-ups, analogs in the art and music worlds, accepted, even celebrated? There’s something about the written word that limits all this unfettered refashioning, something that makes people more protective of their work. It’s the fear of plagiarism, perhaps, or the way that for many people, a character can feel so much dearer than a beat or an image ever could. But fan fiction — and all of its literary counterparts, however you classify them — comes from a place of love and admiration. Some people see a corner of a fictional world waiting to be explored; others just want to exist in the world past the last page of their favorite novel. After all, who among us hasn’t felt that way, closing the back cover of an amazing book and wishing that the author had given us a little bit more?

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