In 1951, Max Theiler of the Rockefeller Foundation received the Nobel Prize in Physiology or Medicine for his discovery of an effective vaccine against yellow fever--a discovery first reported in the JEM 70 years ago. This was the first, and so far the only, Nobel Prize given for the development of a virus vaccine. Recently released Nobel archives now reveal how the advances in the yellow fever vaccine field were evaluated more than 50 years ago, and how this led to a prize for Max Theiler.