Working at the California Institute of Technology, Linus Pauling was the foremost authority on the nature of chemical bonds. In 1948 he found that many proteins take the shape of a single helix, or coil. As Watson and Crick worked on their model, Pauling proposed a triple-helix structure for DNA. Pauling later was awarded two Nobel Prizes, for Chemistry in 1954, and for Peace in 1962, the latter recognizing his work on controlling nuclear weapons and testing.

Credit: Courtesy Ava Helen and Linus Pauling Papers, Oregon State University Special Collections, Box 196?i.