William Peter Blatty: When I was negotiating the film deal. I was staying at the home of Dick Gordon, a Georgetown classmate of mine who was now a law professor at Georgetown Law School. Dick and I were seated in his breakfast nook, talking about what tack to take with the next expected phone call from a producer's Hollywood agent, when the telephone in the living room sounded. My former wife was resting on a living room sofa. The ringing stopped, I heard a clatter, and then my wife kept insisting that she had seen the telephone receiver lift off the hook by itself. When Dick and I entered the room, we did find the phone on The Exorcist arrives
the floor. Dick picked it up, said "Hello." No one there, just a dial tone. He put it back into its cradle, and my wife explained she'd watched it float up off the receiver and drop to the floor. Dick and I were extremely sceptical. Two days later I was sitting right next to that phone, and it was sitting on a very flat surface, and it rang. Being a heavy smoker at the time, I reached for my pack of cigarettes before answering the telephone, and before I could put my hand on it, I watched the telephone receiver life from the cradle, just enough to clear it and fall off the hook. I picked it up, and found that the agent, not a spectral voice, was indeed on the line. Later I called the phone company, got a technician on the line, and asked if the electricity generated by the ringing of the phone might be enough to cause it to jump off the receiver. He said absolutely not, and that he had never heard before of any such occurrence.
Strange occurrences continued to happen. Actor Jack MacGowran died, carpenters received mutilating injuries. The producer decided to call in a priest to bless the set.
Blatty: There was a cessation of these problems after the first blessing and they did not recur until we changed location from New York to Georgetown, and they started again and the same priest, who was my teacher in High School, Father Tom Bermingham, blessed us again and it stopped. Again, as a Catholic and a man of faith I believe within reason that something unknowable was operating on us at the time.
Blatty was inspired to write the story from a true incident that took place in Mount Rainer, Maryland, to a 14-year-old boy back in 1949. His family first heard footsteps coming from the walls, strange scratching noises and accompanying drum beats. His personality became sinister, along with his physical appearance, and red marks emerged on his skin, some of them actually displaying answers, to questions he was asked.
Blatty: The Catholic Church has actually performed very few exorcisms in the United States, in fact as far as I know there have only been three in the past 50, perhaps 60 years. Before allowing such an exorcism to take place, a rigorous investigation is carried out and among the signs of possession are clearly, visible, exterior and undeniably paranormal phenomena.
Charles Moses (Psychic Researcher): When THE EXORCIST came out I think that really started people believing that they had some kind of relationship to possession; either in their family or that they themselves were possessed. It stirred up a lot of interest throughout the world with psychologists and parapsychologists being swamped with calls by people who thought that they were possessed or someone near to them was.
Blatty: Finally, one must ask what really went on. And finally one must say we don’t know. All we do know is that we have no logical explanation for what happened.