This is the story of America's bid to obtain atomic weapons and the aircraft that were developed to deliver them, first tested in July 1945 and the subsequent use of uranium and plutonium bombs on Hiroshima and Nagasaki respectively, an event that pushed Japan to total surrender and the end of the Second World War.Tells the background story of the development of fission weapons, the science behind the engineering, and the colossal effort mobilised by the US, Britain, and Canada to put together what was, at the time, the world's biggest and, at today's cost of $320 billion, the most expensive scientific and weaponized research and development effort in history.Throughout, this story is one of technology, propulsion, design, engineering, and operational deployment of the aircraft. It is not a book about missions, men, or operational activities.