I've just finished rereading THE HOLLOW PLACES, by T. Kingfisher, inspired by Algernon Blackwood's classic tale of cosmic horror, "The Willows." Her earlier book THE TWISTED ONES is a modern-day follow-up to Arthur Machen's deeply unsettling "The White People." I consider THE TWISTED ONES one of the best horror novels I've read in many a year, not excluding Stephen King's recent works. Readers don't have to know the classic stories to enjoy these two novels, but familiarity with their sources enhances the experience. Another recent read, THE HUMMING ROOM, by Ellen Potter, retells THE SECRET GARDEN on an island in the St. Lawrence River in the present day, with other variations. Again, it could stand alone with no knowledge of its model required.
On the other end of the sliding scale of derivative works we find oddities such as PRIDE AND PREJUDICE AND ZOMBIES, which embellishes the classic novel but makes few significant changes other than the insertion of zombies. This type of playing with texts enjoyed a fad after the success of that book. SENSE AND SENSIBILITY AND SEA MONSTERS (by a different author) is more transformative, as are LITTLE WOMEN AND WEREWOLVES and LITTLE VAMPIRE WOMEN (each being exactly what it sounds like). WUTHERING BITES adheres pretty closely to WUTHERING HEIGHTS while taking the obvious step of making Heathcliff a vampire; in the original he's even referred to as one, metaphorically.
Most spinoffs from previous works, of course, are far more transformative to varying degrees. PRIDE AND PROMETHEUS, by John Kessel, introduces Mary Bennet, the bookish sister in PRIDE AND PREJUDICE, to Victor Frankenstein and his creature. PRIDE AND PREJUDICE also inspired a mystery series, at least one portrayal of Darcy as a vampire, and a non-fantastic exploration of Mary's life, THE OTHER BENNET SISTER, by Janice Hadlow. Sequels, prequels, retellings, and side stories to fill gaps in the originals have been written for many classic works. For instance, there's a novel revealing where Heathcliff went during his absence from Wuthering Heights and how he made his fortune. FIVE CHILDREN ON THE WESTERN FRONT is a follow-up to E. Nesbit's FIVE CHILDREN AND IT (and its two sequels) set during World War I. THE WIDE SARGASSO SEA creates a backstory for the mad wife in JANE EYRE. SCARLETT offers an authorized sequel to GONE WITH THE WIND, while THE WIND DONE GONE and RHETT BUTLER'S PEOPLE tell stories parallel to GWTW from viewpoints very different from Scarlett's. John Gardner's GRENDEL gives a voice to the monster in BEOWULF, while Maria Dahvana Headley's THE MERE WIFE translates that epic into contemporary terms. Readers can enjoy the latter without knowing BEOWULF, but they'd need some acquaintance with the original to appreciate GRENDEL. In the decades since DRACULA fell into the public domain, innumerable such books have been published, including two starring Renfield (that I know of) and two novels on the backstories of Dracula's brides by Chelsea Quinn Yarbro (a third was planned but never published). Sherlock Holmes and Peter Pan have enjoyed similar treatment. Marion Zimmer Bradley's MISTS OF AVALON is only one of countless retellings and revisions of the Arthurian legendarium.
Critics who look down on such fiction as "unoriginal" have tenuous ground to stand on. The plots of most of Shakespeare's plays weren't original with him, but were based on history, legend, or prior literary works. "Originality" in the modern sense wasn't highly valued in the realm of literature until relatively recently. Authors who did invent their own stories were likely to make up fabricated sources for them to give them a veneer of respectable antiquity.
One major distinguishing feature of fan fiction is that the reader needs familiarity with the source material to appreciate original stories derived from it; that's true of some professionally published derivative works but by no means all (Kingfisher's horror novels, for example). Why is fan fiction disdained when it does the same kinds of things as the commercially published fiction mentioned above? I've read stories in the universes of BEAUTY AND THE BEAST, FOREVER KNIGHT, and STAR TREK that I consider equal or superior to any of the aired episodes. The only consistent reason for the higher respect granted to the non-fanfic works seems to be their commercial status—which goes along with their legal status, but fanfic based on public domain sources doesn't typically get respect outside its own community, either.
Margaret L. CarterCarter's Crypt