"I think we have to live with the expectation that once every four or five years a nuclear explosion will take place and kill a lot of people." This chilling statement -- McPhee does not identify the source -- about the dangers of peacetime atomic energy represents a common view among those involved, says the author. Spurred by such nonchalance, he explores the men, the reactors and the bombs, organizing his book around the life of Theodore B. Taylor, a theoretical physicist who designed the largest-yield fission bomb ever exploded. After years of building bombs, Taylor experienced a wave of shock and a flash of illumination: "I have a total conviction -- now -- that nuclear weapons should not be used under any circumstances. At any time. Anywhere. Period." Since then Taylor has devoted much of his time to trying to safeguard nuclear materials. He is convinced that uranium and plutonium are inadequately guarded from theft, and that other materials and information needed to build home-made nuclear bombs are accessible to any terrorist who puts his mind to it -- and he makes a convincing case. McPhee's warm portrayal of Taylor and his detailed assessment of current security practices will make your fears mushroom.