Harold Melvin Agnew (March 28, 1921 – September 29, 2013) was an American physicist, best known for having flown as a scientific observer on the Hiroshima bombing mission and, later, as the third director of the Los Alamos National Laboratory.[1] Agnew joined the Metallurgical Laboratory at the University of Chicago in 1942, and helped build Chicago Pile-1, the world's first nuclear reactor. In 19