Although individual pieces of this story have been told before and told well, Rhodes' contribution is in putting together a comprehensive picture of the development of the hydrogen bomb. He depicts the American and Soviet scientific efforts, the internal disagreements among the scientists, the espionage that was critical to the Soviet program, and the strategic dimension of military planning. Particularly with the intelligence story, he does an excellent job of bringing to bear new revelations from the Soviet archives, which document just how comprehensive the Russian effort to penetrate American nuclear and thermonuclear weapons design was. A skillful writer, Rhodes has some vivid descriptions here, including an account of the November 1, 1952, "Mike" test--a 10-megaton blast that scorched a site 14 miles away and, according to Rhodes, churned up some 80 million tons of solid material. One need not agree with his conclusion--that "existential" or minimal deterrence set in at the inception of the nuclear age, and that most of the arms race reflected internally driven developments--to find his overall account highly interesting.