J.K. Rowling, author of the Harry Potter books, has agreed to testify against the publishers of an encyclopedia of the Potter lexicon. Rowling has supported many of the fan-produced spinoffs of her work, but she and her publisher call the new lexicon copyright infringement. “Their objection is that the book merely repackages Ms. Rowling’s work and, unlike the free fan sites, is intended to make money for its publisher.”