the intention for the exorcist

On the heels of Halloween, I'm intrigued by this quote from the writer of "The Exorcist" - the book that the pop culture movie was based on:
"That I am regularly hauled out of my burrow every Halloween like some furless and demonic 'Punxsatawney Phil' always brings a rueful smile of bemusement to my lips as I lower my gaze and shake my head, for the humiliating God's-honest truth of the matter is that while I was working on The Exorcist, what I thought I was writing was a novel of faith in the popular dress of a thrilling and suspenseful detective story—in other words, a sermon that no one could possibly sleep through—and to this day I haven't the faintest recollection of any intention to frighten the reader, which many will take, I suppose, as an admission of failure on an almost stupefying scale. But it's true! … Every [Halloween] I put out the pumpkin with the cutout eyes and nose and face, and the basket full of Snickers and Mars bars beside it; but I do keep wishing—oh, ever so wistfully and—let's face it, hopelessly—that The Exorcist be remembered at this time of the year for being not about shivers but rather about souls, for then it would indeed be in the real and true spirit of Halloween, which is short for the eve of All Hallows or All Saints Day."
—The Exorcist author William Peter Blatty. This October marked the 40th anniversary of his book's publication. And about his inspiration for it, Blatty says, "When I first heard, in 1949, of an actual case of demonic possession and an exorcism going on nearby while I was a junior at Georgetown University, I remember thinking, 'Someday, somebody's got to write about this, because if an investigation were to prove that possession is real, what a help it would be to the struggling faith of possibly millions, for if there were demons, I reasoned, then why not angels? Why not God?'"
[10/28/11]