"We all know I've made enough money," said J.K. Rowling, the author, in a courtroom in New York City this week. "That's absolutely not why I'm here."

It is not obvious, though, why she was there. Along with Warner Brothers Entertainment, Ms Rowling is suing RDR Books, a small, respected publisher in rural Muskegon, Michigan, to enjoin it from selling an A-to-Z guide to Ms Rowling's seven Harry Potter books. This "lexicon" would be based on an online guide compiled over the past decade by Steven Vander Ark in the hours he could spare from his job as a librarian at a Christian junior high school near Muskegon.