Letter, Franklin D. Roosevelt to J. Robert Oppenheimer thanking the physicist and his colleagues for their ongoing secret atomic research, 29 June 1943

Reproduction number: A70 (color slide; pages 1-2)
In the midst of World War II when the United States was engaged abroad in a major conflict with Germany and Japan, it was also working furiously at home toward the completion of the Manhattan Project. This huge research and development project was begun in June 1942 to develop a superexplosive weapon based on the nuclear fission process. It was hoped that such a superweapon would end the war. Two years before such an experimental atomic bomb was detonated successfully near Alamogordo, New Mexico, President Franklin D. Roosevelt (1882-1945) wrote to J. Robert Oppenheimer (1904-1967), the scientist in charge of its development. In this otherwise oblique note of confidence and appreciation, Roosevelt's understanding of the project's significance is made perfectly clear, and he ends his letter with an upbeat morale- booster, suggesting that American science is up to anything the enemy can offer. His confidence was proven justified, as the United States followed its experimental detonation of 16 July 1945 by dropping atomic bombs on the Japanese cities of Hiroshima (6 August 1945) and Nagasaki (9 August 1945), resulting shortly thereafter in Japan's surrender.