Harry Potter and the Order of the Phoenix, J.K. Rowling's great adventure story, is set to start filming in England, according to Warner Bros. In this movie, Potter returns for his fifth year of study at Hogwarts, only to find the school turning a blind eye to his recent fight with the cruel Lord Voldemort. He decides to take matters into his own hands and begins to form. an army of students, whom he trains to defend themselves against the Dark Arts. Daniel Radcliffe, Rupert Grint and Emma Watson again play their roles as Harry, Ron and Herminone, while British director David Yates is to guide the adventure. Rowling released (推出) the sixth book in the series (系列), Harry Potter and the Half-Blood Prince, last July, while the sh and final book is expected by the end of the year. Harry Potter and the Order of the Phoenix is expected for a 2007 release, but there is no word yet whether it will be a summer or holiday movie. How many books about Harry Potter had Rowling finished writing in this text?