The Exorcist (1973)
William Friedkin's 1973 demonic possession drama. Linda Blair as Regan, Max von Sydow as Father Merrin.
Writer: William Peter Blatty
William Peter Blatty won the Academy Award for Best Adapted Screenplay for The Exorcist, from his own novel, and had earlier written comedies including A Shot in the Dark. He based the novel on a 1949 exorcism case reported in Maryland.