Biographical Note: Aurel Wintner (1903-1958) was a mathematician on the faculty of the Johns Hopkins University from 1930 to 1958. Born in Budapest in 1903, Wintner studied at the University of Budapest from 1920 to 1924 but did not take a degree. At the suggestion of Leon Lichtenstein Wintner enrolled at the University of Leipzig where he received his doctorate in 1929. He studied with Tullio Levi-Civita in Rome and with Elis Stromgren in Copenhagen before coming to Johns Hopkins in 1930. During 1937-38 Wintner was a member of the Institute for Advanced Study at Princeton and worked with G.D. Birkhoff at Harvard. In 1941 he was awarded a Guggenheim fellowship and worked with Norbert Weiner. Wintner's work centered on many branches of analysis. His earliest work was on astronomy, celestial mechanics and the theory of Hilbert space. He concentrated on almost periodic functions and/or distribution functions for the period 1930 to 1945, and from 1946 until his death he worked on the theory of ordinary differential equations and differential geometry. Wintner married chemist Irmgard Holder and they had one son Claude.