Although best known as the author of "The Exorcist", the best-selling 1971 novel about a teenage girl's demonic possession which opened the door for a new generation of horrormeisters like Stephen King and Peter Straub, William Peter Blatty actually focused on writing comedy early in his career. All of his work prior to "The Exorcist" was in that genre, beginning with his 1960 novel, Which Way to Mecca, Jack?". His first screenplay credit came for "The Man From the Diner's Club" (1963), and he was working on a script ("What Did You Do in the War, Daddy" 1966) for director Blake Edwards when Edwards replaced the original director of "A Shot in the Dark" (1964), in production as a drama based on the successful play by Harry Kurnitz. Together Edwards and Blatty turned it into a gaspingly hilarious farce, reviving Inspector Clouseau (Peter Sellers) from "The Pink Panther" (1964) as the film's lead. The funniest of the Clouseau comedies, it was one of four collaborations between Blatty and Edwards, ending with "Darling Lili" (1970).

Blatty became interested in exorcism while a junior at Georgetown University, following 1949 newspaper coverage of a reportedly possessed 14-year-old boy. After a 20-year gestation period, this seed became "The Exorcist", and the writer successfully adapted (and produced) the sensational 1973 screen version directed by William Friedkin, winning both the Golden Globe and the Oscar for his screenplay. Blatty returned to comedy for his directorial debut, adapting material from two novels for "Twinkle, Twinkle, 'Killer' Kane/The Ninth Configuration" (1980), an uproarious, yet thought-provoking tale set in a US government asylum where the new head shrink (Stacy Keach) is nuttier than the patients. Its endlessly quotable dialogue helped earn Blatty his second Golden Globe Award (Best Screenplay). Though he had nothing to do with "Exorcist II: The Heretic" (1977), he wrote and directed "William Peter Blatty's 'The Exorcist III'" (1990), based on his 1983 novel "Legion". Not one to abandon a meal ticket, Blatty had been announced as executive produced and writer of yet another version of his most famous work ("The Exorcist"), this time as a TV miniseries but the project stalled in development.