William Peter Blatty, the author of The Exorcist, has died aged 89.
Blatty's widow, Julie, said her husband died at a hospital in Bethesda, Maryland.
The cause of death was multiple myeloma, a form of blood cancer, she said.
Blatty was a former Jesuit school valedictorian who conjured a tale of demonic possession and gave millions the fright of their lives with the best-selling novel and Oscar-winning film.
Blatty's story of a 12-year-old girl inhabited by a satanic force was published in 1971 and sold more than 10 million copies.
The film, starring Linda Blair, came out two years later and its box office topped 400 million dollars (£327 million) worldwide.