For instance, behind every bestselling book are legions of fans who write their own sequels using their favorite author’s characters in slightly altered worlds. These extremely imaginative extended narratives are called fan fiction, or fanfic. They are unofficial—without the original authors’ cooperation or approval—and may mix elements from more than one book or author. Their chief audience is other avid fans. One fanfic archive lists 1.5 million fan-created works to date.
