At the time, Blatty’s story was the newest entry in a lineage of critically acclaimed, popular works from Catholic storytellers during the 1960s and early ’70s that transcended genres and styles. They included the comedic and grotesque fiction of Flannery O’Connor, the philosophical novels of Walker Percy, the beat-Catholic rhythms of Jack Kerouac, the flawless short fiction of Katherine Anne Porter, the terse but complex writing of the convert Ernest Hemingway, the parish stories of J. F. Powers, and the farcical storytelling of John Kennedy Toole, whose novel A Confederacy of Dunces would not appear until after his death. Not to mention the affecting novels from international shores by the likes of Graham Greene, Evelyn Waugh, Shūsaku Endō, and Anthony Burgess.

The era of The Exorcist­ was a time of visible and influential Catholic intellectuals and artists, including two twin prophets of the digital and popular age, Marshall McLuhan and Andy Warhol. Catholic culture of that period was no monolith, though—contrast the conservative William F. Buckley with the more progressive Thomas Merton. The era even saw the rise of culturally Catholic writers, those who retained the language, metaphors, and culture of the church without practiced belief: Cormac McCarthy, Thomas McGuane, and Robert Stone.

Hollywood knew that stories suffused with God could sell. Some of the highest-grossing films in the years adjacent to The Exorcist contained Catholic storytelling or themes without being preachy. There was the sentimental and optimistic representation of nuns in The Sound of Music, Sir Thomas More’s devotion in A Man for All Seasons, the lapsed faith of the lead character in Rosemary’s Baby, religious hypocrisy in The Godfather and its first sequel, the hard-nosed urban Catholicism of Rocky, and the devil’s violence in The Omen.

Despite this tradition, The Exorcist stands as uniquely memorable for its often shocking portrayal of Catholic redemption through suffering. William Friedkin’s film version of Blatty’s novel is true to its source material, but made full use of the cinematic medium and affected audiences like no other film had before.

The Exorcist takes place near the Georgetown University campus in Washington, where the actress Chris MacNeil is shooting a new movie, and living in a rented home with her young daughter, Regan. In an early scene set to the film’s iconic score, Chris is walking home from Georgetown on Halloween. Leaves cover the street, wind blows the habits of nuns as they walk, and children run by in costumes and masks. Chris pauses when she sees two priests rapt in conversation. Viewers only hear snippets: One man says “There’s not a day in my life that I don’t feel like a fraud.”

The priest is a Harvard-trained Jesuit psychiatrist named Damien Karras, a former boxer who’s severe and sullen. He feels like a failure as well as a fraud. He rarely visits his invalid mother in New York City, and when he does, she’s direct with him: “You worry for something. You are not happy.” Back at Georgetown, Karras feels broken, and admits to a fellow priest that he is “unfit” and, bluntly, worries he’s lost his faith. Meanwhile at the MacNeil home, Regan begins to act strangely. After a sequence of exhausting tests, a panel of doctors is baffled, with one member making the unusual suggestion that Chris seek an exorcist for Regan. She meets Father Karras, who’s taken aback by the request. In many ways, he’s more of a skeptic than Chris: Although she doesn’t believe in God, she believes in hope.