How did beloved movie dogs become man-killers like Cujo and his cinematic pack-mates? For the first time, here is the fascinating history of canines in horror movies and why our best friends were (and are) portrayed as malevolent. With behind-the-scenes insights from writers, directors, actors, and dog trainers, here are the flickering hounds of silent films through talkies and Technicolor to the latest computer-generated brutes-the supernatural, rabid, laboratory-made, alien, feral, and trained killers. As one seminal film warned, "They're not pets anymore."