July 1971 The nation's number one best-selling book in recent weeks has been "The Exorcist," a chilling story of a young girl possessed by a demon. The other day its author, William Blatty, a well known Hollywood script writer, visited the B. Dalton book store in Fashion Valley, where he explained how he got the idea for this rather spooky novel to Harold Keen. The film was released December 1973.