Legal disputes over the Harry Potter series October 2007, Warner Bros. and Rowling sued Michigan-based publishing firm RDR Books to block the publication of a 400-page book version of the Harry Potter Lexicon, an online reference guide to her work. Rowling, who previously had a good relationship with Lexicon owner Steve Vander Ark, reiterated on her website that she plans to write a "Harry Potter" encyclopedia, and that the publication of a similar book before her own would hurt the proceeds of the official encyclopedia, which she plans to give to charity. A judge later barred publication of the book in any form until the case was
J. K. Rowling working as a researcher and bilingual secretary for Amnesty International when she conceived the idea for the "Harry Potter" series while on a delayed train from Manchester to London in 1990. The seven-year period that followed saw the death of her mother, birth of her first child, divorce from her first husband and relative poverty until the first novel in the series, "Harry Potter and the Philosopher's Stone", was published in 1997. There were six sequels, of which the last, "Harry Potter and the Deathly Hallows", was released in 2007. Since then, Rowling has written five books for adult readers: