When William Peter Blatty's The Exorcist was published in 1971, he had no idea it would become a national phenomenon. The Exorcist would eventually sell over one million copies and be transformed into a now classic film which Blatty produced and for whose screenplay he received an Academy Award (he also authored the comic masterpiece A Shot in the Dark). Twenty-five years later, the film is still a poignant tale of one man's struggle to believe in God in the twentieth century. And it still packs a punch. Recently re-released in Scotland, it received the same response—and audience—as the first time around. It will be re-released throughout the U.K. this month and may receive similar treatment in the U.S. with a restored 15 minutes that were dropped from William Friedkin's first cut. Currently at work on a novel called Dimiter, a theological thriller set in Jerusalem, and a novella called Elsewhere, Blatty spoke with us on the eve of The Exorcist's silver anniversary.

On a threshold level, The Exorcist does not seem to be a horror movie. Rather, it asks the really big spiritual questions. Were you writing horror or something else entirely different?

WPB: I intended that the novel be an "apostolic" work, one that would either strengthen one's faith or lead one to it. I'd planned it as a non‑fiction exploration of one particular case I'd heard about in 1949. When the real exorcist in that case couldn't get permission from his superior to talk to me about it, I switched to fiction. However, the religious themes so explicit in the novel were—much to my regret—dropped from the film in the course of editing it down to a two‑hour length. However, I note with some pleasure, if not inordinate pride, that a couple of years ago Cardinal O'Connor read excerpts from the novel as part of his homily at Sunday Mass in St. Patrick's Cathedral. I'm guessing that it was the exchange between Karras and Merrin late in the book.

How do you think the film addresses these issues (i.e., transcendency, the nature of people, the spiritual world)?

Only on the most basic level, i.e., if there are immaterial, intelligent forces of evil, this alone suggests the possibility of other such forces that are good. And since the demonic intelligence responds to the ritual used by the Jesuits, it appears that there is God.

The book and film are both titled The Exorcist. Who is the primary exorcist—Merrin or Karras? If it is Karras as I suspect, is the character of Regan really just a side story?

You're right, the exorcist (of the title) is Karras. And Regan's possession is the crucible of his struggle for faith, his salvation.

When you saw the film were you concerned at all that the spectacle of Regan and the special effects would overwhelm the audience and negate anything else you were trying to do with the film?

It never entered my mind. A movie is just a movie. If it holds, it's working.

In the movie version, Father Merrin plays a much larger role than he does in the book, even coming down to the movie poster with Merrin under the streetlamp. How did this come about?

I don't agree with you. It just seems so because so much of Karras is missing.

Conversely, it is not as clear in the movie that Karras is the exorcist of the title as it is in the book.

I think this is an audience misperception problem. It's all there. It's clear.

How much if at all did Friedkin change your vision of The Exorcist?

There is just so much you can do in two hours. Bill Friedkin kept everything he felt would keep the audience gripped to their seats and threw away everything else. I wish it had been otherwise, but I cannot fault him. As Bill told me afterwards, "I didn't know it was going to be a hit."

Most people place The Exorcist within the horror genre. Do you disagree with this?

With much gratitude I recently accepted a "Lifetime Achievement Award" from the Horror Writers Association of America. But as my high school classmate George Paterno (yes, Joe's brother) said in accepting for me, "Bill Blatty is not a horror writer." Before The Exorcist I had a rather nice reputation ("Nobody can write funnier lines than William Peter Blatty," Martin Levin wrote in The New York Times) as a writer of comic novels and films. The Exorcist, in my view, is not horror at all. It is a supernatural detective story. But then what do I know?

Considering that most people took Regan's possession as representative of demonic possession, did you think the film accurately portrayed possession? Do you believe in demon possession?

Yes. In the Western world it's now extremely rare, but back down to ancient Egyptian chronicles we find accounts of possession and exorcism. And since I firmly believe in life after death, there is nothing offensive to my intelligence in the possibility of a discarnate intelligence in rare and extraordinary circumstances taking temporary possession of a shattered personality, as in certain types of serious mental disturbance. Moreover, the New Testament is replete with reports of Christ performing exorcisms.

Have your views changed at all concerning demon possession and the supernatural?

None.

If you were to write it today would you take a different stance?

No.

The movie caused an uproar from critics and audiences alike. Did this surprise you?

I had no idea there would be such a response. As a comedy writer, my hopes for the novel were only that it be taken seriously and that it be received respectably. I had a sense that the novel would be popular, but nothing like what eventually happened. As for the film, at first I thought it simply couldn't be done.

With the rites of exorcism and the actions of Regan once she was "possessed," were these directly drawn from your research or were they spiced up with a little bit of imagination? In both the book and the movie, the sexual prohibition of the priests is set against the destructive perversion of the black mass and the possessed Regan, especially the scene in her bedroom with the crucifix. Was this opposition a burning question in your own mind or did it just set up a striking contrast of good versus evil?

All of the symptomology in the novel came from research. With the film, on the other hand, a couple of things crept in that were a bit over the top, in particular the famed "spinning head," which is not supernatural, but rather impossible. If the head did a 360 it would come off and you'd have a lot of blood. I didn't want it in the film. As for the apparent "opposition," this was never in my mind. Specifically, the crucifix masturbation came about as the result of a mental search for the most hideous and obviously Satanic action I could think of for that point in the story, something that would send an atheist like Chris MacNeil running to priests.

Some critics have seen The Exorcist as a statement about the horrors of adolescence or as reflecting men's anxious relationships with women—either with their mothers or with various aspects of female sexuality. What do you think of these interpretations? Why does Karras's mother (and Regan's) play such a dominant role in the film?

I don't know what to do about such theories. Giggling comes to mind.

What about the end of the film? Is Karras's leap a victory or defeat?

Karras's leap—done only so as to prevent the demon from re‑taking control and then killing the girl—is his total triumph. It is this act—an act of love and self‑sacrifice—that entirely constitutes the exorcism of Regan MacNeil. It was a writer I admire, Ray Bradbury, who saw this most clearly when he referred to The Exorcist as "a great love story." Think about it.