On 2 August 1939, the renowned theoretical physicist Albert Einstein wrote a letter to President Roosevelt in which he declared that "it might become possible to set up a nuclear chain reaction in a large mass of uranium." He went on to declare that "extremely powerful bombs of a new type may thus be constructed." Shortly after Japan's attack on Pearl Harbor, Congress allocated substantial funds to allow research to be undertaken to follow through on Einstein's idea and build an atomic bomb. Few, if any, could have imagined what they had agreed to support. But what if actual events had taken a different course? Dropping the Atomic Bomb on Hirohito and Hitler: What Might Have Happened if the A-Bomb Had Been Ready Early is a highly accurate, thoroughly researched, alternative history presenting a narrative of events exploring what might have happened if the atom bomb had been available somewhat earlier than it really was. What if the atomic bomb had been ready for deployment in, say, February 1945? Had the atomic bomb been ready sooner, how would this have affected the war in Europe, and in particular Germany's surrender? What would the impact have been in the war in the Pacific against Imperial Japan, and how would the Soviets have reacted? And what would the following Cold War have looked like? These are all questions and scenarios that the author rigorously examines. Solidly based on real people and actual events, in this book James Mangi describes the Manhattan Project to build the atom bomb getting an earlier start after President Roosevelt appointed an energetic scientist, Walter Mendenhall, to study the feasibility of the bomb, instead of the more traditional bureaucrat, Lyman Briggs, he actually chose. This scenario, he reveals, might well have produced a war-ending atomic bomb earlier, the effects of which rippled through the post-war world.