Rudolf Criegee (1902-1975) was a German chemist. He studied in Tübingen, Greifswald, and Würzburg and received his doctorate at Würzburg in 1925. He proposed a reaction mechanism for ozonolysis in 1953. The Criegee intermediate and the Criegee rearrangement are named after him. In this context, his research on cyclic reactions and cyclic rearrangement-mechanisms led him, independently of the Nobel-Prize winning work of R.B.Woodward and R.Hoffmann (Woodward-Hoffmann rules), to the same conclusions as theirs, but he failed to publish his findings in time.