J.K. Rowling, the publicity-shy author of the Harry Potter books, will make a rare public appearance in a Manhattan courtroom on Monday in a bid to stop publication of an unauthorised book.

Ms Rowling and Warner Brothers Entertainment, the Hollywood studio that produces the Harry Potter films, are together suing RDR Books to block publication of The Harry Potter Lexicon, an encyclopedic guide to the magical world created by Ms Rowling.