One of the most profitable and well-known horror films of all time, The Exorcist is a 1973 American supernatural thriller adapted from William Peter Blatty's novel of the same name. The film centers around the demonic possession of a 12-year-old girl and her mother's attempts to rid her daughter of the evil spirit through an exorcism conducted by priests. A chilling and frightening film, the true story of Roland Doe, the young man the novel was based on, is even more haunting.