The Exorcist

The Exorcist is a horror novel by the American writer William Peter Blatty, published in 1971 by Harper & Row. It grew out of a newspaper account of an exorcism in 1949 that Blatty had read while he was a student at Georgetown University, and it is set in Washington, D.C., near that campus.

Regan MacNeil is a young girl living with her mother, the actress Chris MacNeil, while Chris is in the city making a film. Regan's behaviour turns violent and she begins to speak in voices that are not her own, and a long series of medical tests fails to explain or cure what is happening to her.

When medicine is exhausted, the church is approached, and two priests, the young Father Damien Karras and the older Father Merrin, are brought in to attempt an exorcism. Karras is a psychiatrist as well as a priest, and the novel follows his struggle to square what he witnesses with what he believes.

The book was adapted into a 1973 film with a screenplay by Blatty, and that adaptation led to a franchise that later grew to include further books and films. The novel is set in the months around the event, and it spends as much time on the clergy and the doctors as on Regan herself.