We've covered in the past J.K. Rowling's attempts to claim that copyright gives her more rights than it actually does, especially with regards to fan fiction. However, Rowling's latest attempt is to try to prevent the publication of "The Harry Potter Lexicon," a fan-created reference book to all things having to do with the world found in the Harry Potter books. Law professor Tim Wu does a nice job explaining why Rowling's claim goes beyond the limitations of copyright law
, which does not prevent someone else from creating a guidebook of information about characters you created. As long as the guidebook creators are not copying Rowling's words verbatim, but are merely creating a guide or a critique of Rowling's work, it's not a copyright issue. Rowling's real problem with the guidebook appears to be a different issue. She had no problem when the Lexicon was just a fan website. However, when they wanted to sell a book, she became upset. So the real problem appears to be that she doesn't want anyone else to make any money -- but that's not what copyright law is designed to do. Newspapers make money off of books all the time by publishing reviews, and we all know that's legal. There is no difference in creating a reference book.
Rowling complains that this work will make it difficult for her to publish her own guidebook: "I cannot approve of 'companion books' or 'encyclopedias' that seek to preempt my definitive Potter reference book...." However, as Wu notes, that's silly and has nothing to do with copyright law: "two products in the same market isn't called pre-emption—the word is competition." And, generally, competition is something that we should encourage, as it drives all competitors to provide better products. If Rowling really believes she cannot compete with a fan reference guide, that's hardly the fault of the other reference guide. Given the interest in Harry Potter, it's hard to believe that an "official" reference guide given Rowling's endorsement wouldn't outsell any fan-created version.