Born: January 23, 1876; Hamburg, Germany Died: March 7, 1950; Kiel, West Germany Area of Achievement: Chemistry Contribution: Diels made two fundamental contri-

butions to classical organic chemistry: the selenium dehydrogenation and the diene reaction. The selenium reaction made it possible to establish the structure of a large number of important natural materials, notably the steroids. The diene reaction is unique in its variety, durability, and quality.