Late in 1997, film producer David Heyman's London offices received a copy of the first book in what would become Rowling's series of seven Harry Potter novels. The book, Harry Potter and the Philosopher's Stone, was relegated to a low-priority bookshelf, where it was discovered by a secretary who read it and gave it to Heyman with a positive review. This fateful act influenced Heyman, who had originally disliked "the rubbish title", to read the book himself. Highly impressed by Rowling's work, he began the process that was to lead to the most successful cinematic franchise of all time.
Heyman's enthusiasm led to Rowling's 1999 sale of the film rights for the first four Harry Potter books to Warner Bros. for a reported £1 million (US$2,000,000). A demand Rowling made was that the principal cast be kept strictly British, allowing nevertheless for the inclusion of many Irish actors such as the late Richard Harris as Dumbledore, and for casting of French and Eastern European actors in Harry Potter and the Goblet of Fire where characters from the book are specified as such. Rowling was hesitant to sell the rights because she "didn't want to give them control over the rest of the story" by selling the rights to the characters, which would have enabled Warner Bros. to make non-author-written sequels.