This careful scholarly monograph, which makes its appearance the morning after the bitter controversy aroused by the 50th anniversary of Hiroshima, is "post-revisionist" in tone and outlook. The author, the historian of the U.S. Nuclear Regulatory Commission, acknowledges that some officials saw diplomatic benefits vis-a-vis the Soviets from the use of the bomb but insists that such motivations were of decidedly secondary importance. He also disputes the conventional interpretation that Truman faced a clear choice between using the bomb and ordering a U.S. invasion that would have brought hundreds of thousands of American casualties. Those high estimates, he argues not entirely convincingly, were ex post facto rationalizations brought on by the need to justify a terrible act; the estimates made at the time were much lower. The author's ability to cover the most important issues with economy, together with a thorough bibliographical essay at the end, make this an excellent addition to the literature, particularly useful for beginning students.