William Friedkin didn't consider The Exorcist a horror movie. He thought there was nothing supernatural about it, emphasising how the story was based on the real-life exorcism of a 13-year-old boy known as Roland Doe, in Maryland, 1949. But boy, did his film scare the bejesus out of everyone, achieving recordbreaking success (10 Oscar nominations, $441m at the worldwide box office) and ushering in waves of prestige studio horror movies, cheap possession knockoffs and devil pictures.
