How The Exorcist Differs From The Book

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There are many excellent horror films out there that could be considered in the running for the title of "the scariest." While the matter is subjective, few films can stake as large a claim on the title as "The Exorcist" from 1973. The film proudly declares itself "the scariest film of all time" on some posters and is routinely named the best horror film ever made.

After winning the Academy Award for Best Director for his 1971 crime film "The French Connection," William Friedkin made "The Exorcist" as his next movie. His efforts landed him another Best Director Oscar nomination alongside a staggering nine additional Academy Award nominations, an extreme rarity for the horror genre. The film took home the Oscars for Best Sound and for Best Adapted Screenplay. William Peter Blatty wrote the novel "The Exorcist" and then adapted his own work when writing the screenplay and winning the Oscar. Blatty was no stranger to screenwriting, having earlier written movies like the "Pink Panther" sequel "A Shot in the Dark."

Given that the original author of the source material returned to write the screenplay, it makes sense that "The Exorcist" is quite a faithful film adaptation. Even still, there were a number of significant changes made between the book and the film. Here are the biggest ways that "The Exorcist" movie differs from the original novel.

The book version of "The Exorcist" spends the vast majority of its length — arguably its entire duration — maintaining a level of ambiguity as to whether or not Reagan is truly possessed. In the film version, it becomes clear relatively early on that Reagan is possessed. Seeing the supernatural, demonic happenings with one's own eyes strips away much of the ambiguity and mystery found in Blatty's prose.

No matter how extreme Reagan's ailments may be or how supernatural her actions may appear, the novel goes to great lengths to always offer a possible alternative explanation outside of possession. The alternatives may sound far-fetched, but they are presented as having a basis in science, and characters even offer real-world case studies of similar unexplained phenomena happening around the world. In the book, Reagan might be possessed by a demon, but then again there's always a slim chance that she is instead afflicted with severe physical/mental ailments. By the end of the book, the odds certainly seem in favor of the possession being genuine, but the door was left ever so slightly open for it to have been a medical anomaly instead. As noted by The Washingtonian, Blatty was sure to always balance out the potential supernatural happenings with the "matter-of-fact minutiae of a clinical case study" and "a backdrop of solid theology."

Part of what makes "The Exorcist" such a terrifying film is the shocking extent of its explicit language, blasphemy, and violence involving a 12-year-old girl. Some of the most disturbing scenes involve the possessed Reagan acting out in aggressively sexual ways such as masturbating with a crucifix and shoving her mother's head in between her legs while screaming "lick me!" As shocking as those scenes were and remain today, the book pushed the explicit content even further.

Of course in the film version of "The Exorcist," with a real young actress in the role (Linda Blair was 14 at the time of the film's release), certain lines needed to be drawn, particularly in regards to the demon's sexual acts but also in regards to its most explicit language. Those limitations did not apply to William Peter Blatty's Prose in the novel. One recurrent tactic of the demon to humiliate and torment Reagan and Chris MacNeil in the book is to make Reagan commit sexually explicit acts and speeches in front of company.

One significant subplot from the book that didn't fully make it into the movie involves desecrations at the local church and the holding of Black Mass ceremonies. The film version of "The Exorcist" doesn't drop this thread entirely, but drastically reduces its scope and screen time. One desecration is shown in the movie, and Lt. Kinderman does briefly mention the notion of a Black Mass, but the film takes it no further. The book contains descriptions of additional desecrations and, even though the one desecration shown in the film is quite graphic, the book pushed the desecrations much farther. They involved an explicit, blasphemous story written on an altar card and the incorporation of all manner of bodily fluids in sickening ways.

In the film, Lt. Kinderman asks Karras for information about the desecrations and Black Mass ceremonies, but what the film leaves out from the book is that Father Karras was Lt. Kinderman's primary suspect in the desecrations for a time. He is established as an expert in Black Mass rituals, and his public crisis of faith paired with the recent death of his mother gave him a motive for committing the desecrations our of a resentment toward the church. Also absent from the film is a definitive answer to who caused the desecration(s). In the book, Lt. Kinderman sniffs out a series of clues that point to the desecrations being committed by Reagan during the early stages of her possession. The note on the altar card was written in Latin using Sharon's typewriter, and the type of paint used in the desecrations matches the paint used on Reagan's handmade sculptures.

Burke Dennings is the director of the movie that Chris is shooting at the beginning of "The Exorcist." He is also the man who has his head turned all the way around before getting thrown from Reagan's bedroom window and down the now-iconic flight of stairs in Georgetown. In the movie, Dennings is a minor character who helps set the plot in motion and brings Lt. Kinderman in to investigate, but he had a much larger role in the novel version of "The Exorcist." His prominence in the novel is owed partly to the overall book spending significantly longer developing all of the characters at the start of the story before getting into the possession.

Much more is divulged about Dennings' personality, career, and even his personal and family life in the book. There's a real sadness and sense of loneliness that gestates within him, and he spends a great deal more time at the MacNeil household whenever they aren't shooting the movie. There is a closeness between him and Chris in the novel that runs deeper than what is portrayed in the film. Though the two verbally spar and get on each other's nerves, they do genuinely care about each other, and his death takes a heavy toll on Chris. In the film, he is seen drunk and belligerent at Chris's dinner party, but this is a more common occurrence in the novel, with his foul-mouthed character embodying a case of full-blown alcoholism.

Though Father Karras and Lt. Kinderman are both in the movie, their dynamic is quite different than it was in the book. They only share one real scene together, and it serves mostly as a simple exchange of information. In the book, however, they share many scenes and get to know each other quite well. Though they find themselves at odds when it comes to matters of faith and the supernatural, and Kinderman even initially suspects Karras of being the one committing the desecrations, they form something of a friendship and learn to genuinely enjoy each other's company.

They bond over a love of movies, discuss plans to go to the theater together, and chat about plenty of subjects that have nothing to do with the investigation at hand. They even take the time to relocate to a nice vantage point to watch the sunset together. The only sliver of this dynamic to make it into the movie comes with both expressing an interest in cinema, but they don't form any sort of bond on screen.

Interestingly, some of the cut dialogue between Father and Karras and Lt. Kinderman would later be repurposed by William Peter Blatty when he wrote and directed "The Exorcist III" adapted from his novel "Legion." Instead of transpiring between Lt. Kinderman and Father Karras, the dialogue now transpires between Kinderman (now played by George C. Scott) and Father Dyer (now played by Ed Flanders). The carp scene in "The Exorcist III" is an example of a scene originally included in novel version of "The Exorcist."

One memorable supporting character from the novel is Captain Billy Cutshaw, an astronaut scheduled to head into space. He attends Chris's dinner party and is one of the guests of honor. The character does appear briefly in the film, but his role was drastically reduced. In the film version of "The Exorcist," he isn't given a name, and the actor who played him, Dick Callinan, wasn't even credited. When Reagan wanders into the dinner party early on in her possession, she tells the astronaut, "you're going to die up there," before urinating on the carpet.

Though the astronaut in the film is a tiny character with only a brief moment of screen time, he was an incredibly important character for William Peter Blatty. Captain Billy Cutshaw doesn't just exist within "The Exorcist," he is also in William Peter Blatty's novel "The Ninth Configuration." Rather than appearing again as a supporting character, Cutshaw is one of the two main protagonists of "The Ninth Configuration." The novel is set in a military asylum, into which Cutshaw self-admitted after having a breakdown prior to space launch and fleeing. Reagan's words about "dying up there" really got to him.

Another major element of the novel that didn't entirely make it into the film is all of the red tape involved in getting the Catholic church to approve of conducting an exorcism. This issue factors into the film in a limited way, with Father Karras mentioning that he would need proof of possession to get approval for an exorcism, but the novel devotes far more time to this endeavor. Throughout the vast majority of the novel, Karras spends his time navigating the church's red tape.

This is an ordeal that takes him several days and sleepless nights, as he delves into research and investigations. He studies abnormal physical phenomena, researches past exorcisms, cross-references all of Reagan's symptoms with every bit of available medical data, and goes to great lengths to rule out any possible explanation outside of possession before finally putting in an exorcism request. Karras's crisis of faith and skeptical nature mean he needs to convince himself that the possession is genuine beyond all doubt, not just convince the church. Conducting an exorcism on a young girl who is not truly possessed would have dire consequences and could be extremely dangerous to her well-being.