In 1943, the Manhattan Project formed a United States Army contingent to work on the atomic bomb - called the Special Engineering Detachment (SED). Several hundred SEDs, including Benjamin Bederson, were assigned to Los Alamos where they often acquired positions of responsibility far in excess of their army rank. In this memoir, Bederson describes his experiences at Los Alamos and on the island of Tinian, from which the bombs were delivered to Hiroshima and Nagasaki. An interesting by-product of the SED was that it served as a breeding ground for many distinguished physicists and mathematicians.