Among the myriad controversies surrounding the American use of nuclear weapons against Japanese cities in August 1945 is the seemingly simple question of exactly when President Harry S. Truman decided to use the bomb. The closest thing to a presidential directive regarding use was an order dispatched on July 25, 1945 from Acting Army Chief of Staff Thomas T. Handy to General Carl A. Spaatz, commander of the United States Army Strategy Air Forces. The directive, personally approved by Secretary of War Henry L. Stimson, authorized the delivery of the “first special bomb as soon as weather will permit visual bombing after about 3 August 1945…” The bomb was to be used on one of four target cities (a list that included Niigata and Kokura as well as Hiroshima and Nagasaki) and no further orders were required for the use of additional bombs, which were to be “delivered on the above targets as soon as made ready by the project staff.” But while this directive was almost certainly discussed with the president before its approval, Truman never signed this or any other order with respect to the use of the atomic bomb against Japan. More significantly, the order was itself the product of an extended series of discussions and decisions that in some cases went back months or even years prior to the summer of 1945. While significant as a link in the chain of operations that culminated in the atomic bombings of August 6 and 9, historians must look beyond the July 25 directive to understand exactly when and how Truman committed to the use the bomb.