After overseeing the construction of the uranium and plutonium plants, Groves moved on to the actual construction of the bomb. In October 1942, he selected J. Robert Oppenheimer to direct the scientific research and design of the bomb. Oppenheimer had attended Harvard University during the 1920s. He had also studied physics with Chadwick and Rutherford in Great Britain. He earned his doctorate in Germany where he gained an international reputation as a physicist. When Oppenheimer returned to the United States, he got a job at the University of California. There he became a leader in atomic research. It was while he was working in California that he was chosen by Groves to direct the scientific effort of the Manhattan Project.

Oppenheimer and Groves were in agreement that the Manhattan Project needed a central laboratory where scientists could collaborate on theoretical...