Photograph of Otto Hahn (1879-1968), German chemist, Nobel Laureate and discoverer of nuclear fission. Hahn's family wanted him to be an architect, but he was eventually allowed to study chemistry at Marburg. After his doctorate, Hahn studied with Ramsay in London then Rutherford in Canada. He returned to Germany in 1910. It was in the 1930s that he did his most important work. On bombarding uranium nuclei with slow neutrons, he detected the production of barium rather than the radium he expected. Against the knowledge of the day, he suggested that the nucleus had been split. He reluctantly published in 1938, and received the 1944 Nobel Prize for Chemistry.