The Exorcist is a play by John Pielmeier based on the novel of the same name by William Peter Blatty and is part of The Exorcist franchise. The story revolves around a young girl, Regan MacNeil, who is possessed by a demonic spirit. Her mother, Chris, seeks out to the church to perform an exorcism.

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.