Few events of the twentieth century have received as much sustained attention from historians, or been the subject of such enduring controversy, as the atomic bombing of Japan in August 1945. The predominant focus of interest has tended to be on the sequence of events that, along with the motivations of the principal antagonists, led to the attacks that devastated Hiroshima and Nagasaki, with all the terrible human suffering that they involved. Set against repeated efforts to defend the use of the bombs as a means to shorten the war have been accounts which have variously branded the action as needless, in that Japan's surrender was imminent, as a morally reprehensible example of targeting a civilian population for mass destruction, and as partly driven by a political desire to demonstrate American power, not least to intimidate a Soviet Union which was already emerging as a dangerous potential post-war rival to the United States. Many choose, moreover, to look at Hiroshima and Nagasaki either as the coda to a world war of unmatched scope and intensity, or as opening signals for the international tensions, and incipient destructive potential, that would come to characterize the soon to develop Cold War. Virtually all studies recognize that the first operational use of the bomb marked a watershed in conceptions of war and the development of strategic thought.