From Reuters:

Billionaire Harry Potter author J.K. Rowling would feel “exploited” if a fan’s unofficial encyclopedic companion to the boy wizard series was published, she said in court papers made public on Thursday.

Steve Vander Ark has written The Harry Potter Lexicon “ a 400-page reference book based on his popular fan Web site (www.hp-lexicon.org). Rowling and Warner Bros. are suing RDR Books, which planned to publish the book last November.

“I am very frustrated that a former fan has tried to co-opt my work for financial gain,” Rowling, 42, who wrote the seven hugely successful Harry Potter novels, said in a declaration filed in U.S. District Court this week.

We’re not copyright lawyers, but we’re pretty sure that lexicons, literary guides, book-length exegeses, annotated editions, and literary companion volumes existed long before little Harry took his first trip aboard the Hogwarts Express.

(And note how Rowling dubs Ark a “former fan” “ zing!)