Warner Bros. Entertainment, Inc. v. RDR Books
United States District Court for the Southern District of New York
375 F. Supp. 2d 513 (2008)
Vander Ark (defendant) created and continually updated a Harry Potter fan website (the Lexicon) cataloguing characters, places, and details from J.K. Rowling's (plaintiff) book series, which RDR Books (defendant) later proposed turning into a published book with alphabetically organized entries that included extensive direct quotations and close paraphrasing from the novels, some without quotation marks; Rowling and Warner Bros. (plaintiffs), who owned the movie rights, sued for copyright infringement before the Lexicon book's publication.
Whether companion guides or reference materials for fictional works constitute derivative works under section 101 of the Copyright Act.