The formula Koontz ( The Bad Place ) uses here is a familiar one: an overpowering evil stalks an innocent family that remains unaware of the menace until isolated from all help and forced to run for their lives. But enhanced by Koontz's lean prose and rich characterization, this fearsome tale summons up new frissons of horror. Marty Stillwater's second horror novel is bestseller-bound; he's the subject of a People magazine feature article; and his wife, Paige, and their two young daughters complete the perfect family. Then he begins having blackouts and paralyzing panic attacks that lead him to hide guns around the house. The weapons prove handy when an armed stranger--Marty's Doppelganger --breaks into the house to kill him and reclaim the life, family and destiny that he swears Marty stole. A fierce battle leaves the stranger dead but when Paige and the police arrive, the body is gone. Unable to trust the cops, the family runs for the hills to try to evade the seemingly indestructible "Other." Meanwhile, sinister agents are desperately tracking The Other for their own less-than-ethical ends. Playing on every emotion and keeping the story racing along, Koontz masterfully escalates the tension. He closes the narrative with the most ingenious twist ending of his career. Literary Guild & Doubleday Book Club main selection; Mystery Guild alternate selection. Copyright 1993 Reed Business Information, Inc.