William Peter Blatty was an American writer, director and producer. He is best known for his 1971 novel, The Exorcist, and for his 1973 screenplay for the film adaptation of the same name. Blatty won an Academy Award for Best Adapted Screenplay for The Exorcist, and was nominated for Best Picture as its producer. The film also earned Blatty a Golden Globe Award for Best Motion Picture – Drama as producer.

The Exorcist is a 1971 horror novel written by American writer William Peter Blatty and published by Harper & Row. The book details the demonic possession of eleven-year-old Regan MacNeil, the daughter of a famous actress, and the two priests who attempt to exorcise the demon. The novel was the basis of a highly successful film adaptation released two years later, whose screenplay was also written and produced by Blatty. More movies and books were eventually added to The Exorcist franchise.