I guess at that time he was best known for having written the novel and screenplay for "The Exorcist". IMDB tells us that Blatty regarded The Ninth Configuration as a sequel to The Exorcist.
He only went on to direct one more movie, "The Exorcist III" in 1990.
I saw The Ninth Configuration on video shortly after it was released. It's a great movie and I never forgot it.
The movie has everything: comedy, tragedy, mystery, action, and really great dialogue. And it's thought-provoking too. Great performances by Stacy Keach, Scott Wilson, and Ed Flanders.
I watched it again today, after all these years. I wasn't disappointed.
My rating: 8/10.
Here's a still from the movie showing Keach as Col. Kane and Blatty in an uncredited role as Dr. Fromme:
