Having seen the movie and its sequels numerous times, and having read a lot of articles and ‘scholarship’ on the film, I am now doing what I never dared to before: reading the novel! (I’ve already had a nightmare, and had to sleep with the TV on)

Already a few things are sticking out at me (and I haven’t finished the book yet, so it could all be going nowhere, but it is interesting to think about it).

The novel seems much more concerned with so-called ‘satanism’ and ‘Black Mass’ than the film. The ‘witchcraft’ book and Karras/Kinderman’s research all set the stage for us, as well as the time spent on details of the church desecration. The medium, Mary Jo Perrit (an interesting character that was dropped for the film) warns Chris McNeil about the Ouija. There’s also the suggestion that Regan read the book that Mary Jo Perrit brought her, thus influencing her possessed behavior.

I just found it odd that Karras expressed a belief in Black Masses being common in Europe. I know he’s a priest, but he’s also presented as a rational scientist, trying to painstakingly prove that there was nothing supernatural about Regan’s affliction. It was also kind of odd when he stated that psychokinesis was a common, scientifically provable occurrence. (Could that just be a product of the times? I know serious scholarly research into psychic phenomenon was common in the 60’s and 70’s).

Then there’s Karl. I don’t know the outcome of this subplot with his daughter and the drugs he stole at his previous job. But he is very fishy – and wasn’t it implied that he could have been planting various things in Regan’s room, such as the cross and the witchcraft book? So what was he doing? Dennings kept calling him a Nazi. The paint used in the church desecration matched Regan’s paints. Now I could either picture Regan levitating out of her window and breaking into the church at god knows what hour (plausible, but a “much too vulgar display of power” as the demon might say), or, did Karl do it? was Karl some sort of European satanist responsible for the possession? A bit too ‘Rosemary’s Baby’ of an idea that I don’t necessarily like, but there you go.

Reading the novel really freaked me out: in my head, I blended it with the sounds and imagery from from the film and had nightmares for weeks!

Bad Locust, right there with you!  I just finished the novel for the first time.

 

Yes, I share your annoyance that ideas like tele/psychokinesis and telepathy were considered to be part of the "rational, proven, scientific fact" side of Blatty's calculus while all the occult stuff was on the other side.  But this was indeed a product of its time.  During this time you had a lot of pseudoscience posing as real science in popular culture— "In Search Of" hosted by Leonard Nimoy (lending his logical veneer to the charade) comes to mind.  A children's show called "The Tomorrow People" became popular in the 1970s, which posited that the next stage of human evolution would weild powers like telepathy and telekinesis.  It was definitely something in the air around that time.

 

Of course, by now we know that all these paranormal "scientific" claims had no validity at all.