Arnold Feldman started college at Penn State when he was 16 and graduated with a degree is physics. He was drafted into the Army and was doing his basic training in Louisiana, when his sergeant told him he was going to New York City. When he asked why, he was told, "They will tell you when you get there." Eventually he was sent to Los Alamos.
Feldman and six other members of the group of physicists at Los Alamos formed the group American Academy of Physicists in Medicine after the war.
For more about Feldman, please see the article A view from the dawn of the bomb.