Jack Thorne's play 'Harry Potter and the Cursed Child' is based on the original story by J.K. Rowling, John Tiffany, and Jack Thorne. It is the eighth Harry Potter book and the first official stage adaptation. This version of the script is the final version and includes additional material: a family tree of Harry Potter's family, a timeline of key events in Harry Potter's life, and a conversation between John Tiffany and Jack Thorne about the script.