William Peter Blatty
William Peter Blatty (January 7, 1928 – January 12, 2017) was an American writer, screenwriter, and movie director. The novel The Exorcist, written in 1971, is his most well-known novel. He was the screenwriter of the movie adaptation. He won an Academy Award for it. He also wrote and directed the third movie of the trilogy, The Exorcist III.