Maddox (History/Penn. State Univ.; The New Left and the Origins of the Cold War, 1973, etc.) argues that President Truman decided to use the atom bomb for exactly the reasons he gave in his official statements: to compel Japan to surrender without an American invasion. Contrary to the arguments made by revisionist historians, Maddox shows that, based on the information available to Truman and American military leaders at the time, the dropping of the atomic bombs appeared a military necessity. He argues that the Japanese military, far from being prepared to surrender, favored strong resistance to the end in an effort to inflict massive American casualties: The author cites bellicose statements by Japanese army leaders after the emperor had ordered surrender to prove that the Japanese desire to fight was still strong. Maddox also shows that, contrary to the contentions of revisionists who rely upon ``obsolete casualty estimates that never were conveyed to Truman in the first place,'' Truman's public estimate of a half-million American casualties in an invasion of Japan was both an honest and conservative estimate. Finally, the author argues that Truman's conduct during and after the Potsdam conference, and American contemporary offers to share nuclear technology with the UN, were incompatible with an American plot to intimidate the Soviets with the bombings and, because of Stalin's suspicious nature ( and a nuclear weapons research program that he initiated in 1943), unlikely to prevent the nuclear arms race that resulted. Maddox's study will not put an end to the controversy (which has been the subject of a spate of recent books) or to the endless ``what-if'' speculations over whether Japan would have surrendered without the bombings. Still, he makes a well-reasoned contribution to the scholarly debate that reminds us of the political context in which Truman actually made his decision.