The ExorcistFor millions of readers, William Peter Blatty's The Exorcist remains the most terrifying novel ever written; and the filmwritten by Blatty and directed by William Friedkinis still, 50 years after it was first released, one of the most shocking films ever made. Father Damien Karras: "Where is Regan?" Regan MacNeil: "In here. With us." The terror begins unobtrusively. Noises in the attic. In the child's room, an odd smell, the displacement of furniture,