George Simms Hammond was a chemist at Iowa State University and the California Institute of Technology. He was born on 22 May 1921 in Auburn, Maine, U.S. He attended nearby Bates College in Lewiston, Maine where he graduated Magna Cum Laude with a B.S. in Chemistry in 1943. He completed his doctorate at Harvard in 1947. Among his awards were the Norris Award in 1968, the Priestley Medal in 1976, the National Medal of Science in 1994, and the Othmer Gold Medal in 2003. Hammond was a leader in the field of photochemistry and was widely credited with creating the discipline of organic photochemistry. Hammond's postulate, also known as the Hammond-Leffler postulate, was based on his 1955 publication. He died on 5 October 2005 in Portland, Oregon, U.S.