Gustavus John Esselen (1888–1952) was an American chemist born in Roxbury, Boston, Massachusetts. He studied at Harvard University where he was awarded the A.B. (magna cum laude) in chemistry in 1909 and a doctorate in 1912. Until 1921 he was a member of the research staff of General Electric and then of Arthur D. Little. There with Little and Wallace Murray he contrived to make a 'silk' purse from reconstituted collagen extracted from a sow's ear. In 1930 he founded Gustavus J. Esselen, Inc., which following a merger, became Esselen Research Division of United States Testing Co., Inc. Among the successful projects for industrial clients he was involved with was the development of anhydride curing agents for epoxy resins and polyvinyl butyral as an improved material for the subsequent commercialization of laminated glass for use in vehicles etc. More than 40 U.S. patents were issued as a result of his research efforts. He was a member of the American Chemical Society for 43 years, twice chairman of the Northeastern Section (1922–23) and served as councilor and director of the national organization. From 1919 to 1951 he was chairman of the American Section of the Society of Chemical Industry. Prior to World War II he was a reserve officer in the U.S. Army's Chemical Warfare Service. During the war he was a committee chairman with the Office of Scientific Research and Development.