Excellent, if somewhat outdated by being 50 years old. Sherwin provides a brisk look at the fractured decision processes around the bomb's development and use. He skips most of the technical details (read Rhodes' masterpiece for that), cataloging how the changing diplomatic situation shaped the plans for the nuclear program, and vice-versa.

As for the big question—how did we decide to drop the bomb on Japan—it reminded me a lot of Sherwin's later (even better) Cuban Missile Crisis book. In both cases, decisions were arrived at before anyone had time to ask the questions, simply because they grew out of assumptions that were too baked in at that point. Thankfully for us all in the '60s, the Kennedy Administration had the time and attention to re-evaluate things before deciding to strike. Truman simply didn't have the capacity or interest, and the actual decision-makers were marginally more flexible.