Famed Harry Potter author J. K. Rowling is to testify in a New York court Monday, against the publication of “The Harry Potter Lexicon,” a book written by a fan based on her work.

J. K. Rowling, the British author of the Harry Potter series, and movie studio Warner Bros., which owns the intellectual property related to the Potter books and movies, brought a copyright infringement lawsuit against Steve Vander Ark and RDR Books in October 2007.

“The Harry Potter Lexicon,” written by Ark, who is also editor of the website www.hp-lexicon.org, was to be published last November via RDR Books, a small Muskegon, Mich., publisher.

The book’s release was put on hold following the legal situation.

Rowling contends the “Lexicon” represents the kind of copyright infringement she has been striving to stop throughout the years. “I am deeply troubled by the portrayal of my efforts to protect and preserve the copyrights I have been granted in the Harry Potter books,” papers filed in late February said.

“I believe that RDR’s book constitutes a Harry Potter 'rip off' of the type I have spent years trying to prevent, and that both I, as the creator of this world, and fans of Harry Potter, would be exploited by its publication,” she added.

Rowling also said she is troubled that the unpleasant situation stems from a fan website which she has praised in the past.

Judge Robert P Patterson will hold the trial without a jury at the Daniel Patrick Moynihan courthouse in the Southern District of New York. The case is scheduled to last for most of the week, according to the BBC.

Should RDR win in court and go ahead with the publication of the lexicon, Rowling fears that this “will undoubtedly have a significant, negative impact on the freedoms enjoyed by genuine fans on the Internet.”

“Authors everywhere will be forced to protect their creations much more rigorously, which could mean denying well-meaning fans permission to pursue legitimate creative activities,” the writer said.

Ark’s 400-page book is based exclusively on Rowling’s writing. As does his website, the lexicon offers comprehensive details on spells and potions found in the books, characters’ full names and biographies, lists of magical creatures etc.

Rowling is seeking in her lawsuit an injunction blocking publication of the book which she says would interfere with her own plans to publish an encyclopedia of the boy wizard’s world.

RDR Books publisher Roger Rapoport has said the lexicon is a “critical reference work” that would not compete with Rowling’s own encyclopedia.