This paper assesses and compares the impact and historical significance of the firebombing and atomic bombing of Japanese cities in the history of war and the history of disaster. Japan's decision to surrender, pivoting on issues of firebombing and atomic bombing, Soviet entry into the war, and the origins of Soviet-American confrontation, is the most fiercely debated subject in twentieth century American global history. The surrender question, however, is addressed only in passing here. The focus is rather on the human and social consequences of the bombings, and their legacy in the history of warfare and historical memory in the long twentieth century. Part one provides an overview of the calculus that culminated in the final year of the war in a US strategy centered on the bombing of civilians and assesses its impact in shaping the global order. Part two examines the bombing in Japanese and American historical memory including history, literature, commemoration and education. What explains the power of the designation of the postwar as the atomic era while the area bombing of civilians by fire and napalm, which would so profoundly shape the future of warfare in general, American wars in particular, faded to virtual invisibility in Japanese, American and global consciousness?