Hiroshima - The World's Bomb (2008) (THE MAKING OF THE MODERN WORLD)

The title of this book is somewhat misleading as it covers far more ground than simply an account of the atomic bombing of Hiroshima. The book traces the development of the A-bomb (though at a high level, and the reader interested in this subject would be far better off reading "The Making of the Atomic Bomb" by Richard Rhodes). Alongside this the author lays out the parallel development of strategic bombing and the degeneration of morals on all sides as a result of the brutalities of the World War, both of which contributed to the climate in which the decision to use the weapon was made. The actual description of the events at Hiroshima takes up very little space as the author moves on to describe (again at a high level) the subsequent proliferation of nuclear weapons almost to the present day.
The book adopts a clear moral stance as regards the bombing, and while hedging somewhat, it is clear the author does not believe the bombings were a necessary part of winning the war against Japan. The decision to use the bomb is presented as almost inevitable with few of those involved expressing any serious moral reservations at the time. Furthermore, the author appears to believe, the bombings were far more a geopolitical statement to the Soviet Union rather than a military step to defeat Japan.
Unfortunately the book offers little new on the subject other than the idea that the bomb was the "world's bomb". This idea is based on the multi-national nature of the scientists that developed the theory and practical usage of the nuclear weapon and on the moral climate that made its use feasible. These are thin arguments at best. While the theoretical developments in early 20th century physics were certainly spread across the international scientific community, the Manhatten Project, despite critical contributions from the British and European scientists, was very much an American endeavor. More importantly, the decision to use the weapon was entirely an American one. As to the moral climate of the times, few if any, of the leaders of the Allied or Axis powers would have demurred from using the bomb had it been available to them, and a majority of their populations would have supported that decision. But this does not constitute a basis for calling it the "world's bomb". In all honesty the bomb was clearly an American Bomb with all that entails.
As for the history of the bomb and the associated physics this is better described in Rhodes' excellent book, the history of air power and the war in general can be found in specialist works covering those domains, and the arguments for and against the use of the bomb are well known to anyone familiar with 20th century history.
If you are unfamiliar with this subject matter then the book is a good overview. If you are familiar with the subject then this work will likely add little to your knowledge.