In the midst of World War II, while engaged abroad in a major conflict with Germany and Japan, the United States 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