Stefan Banach

Born in Kraków on 30 March 1892 to a family of Goral descent, Banach solved math problems during school recess and carried that intensity into adulthood. A friendship with Hugo Steinhaus after secondary school led to the founding of the Polish Mathematical Society in 1919 and the launch of Studia Mathematica. By 1920 he had an assistantship at Lwów Polytechnic; two years later he was a professor, and by 1924 a member of the Polish Academy of Learning. He co-founded the Lwów School of Mathematics, a powerhouse of interwar Polish thought. His 1932 Théorie des opérations linéaires became the first monograph on functional analysis as a unified theory. He died 31 August 1945, leaving a lexicon: Banach spaces, the Banach-Tarski paradox, the Hahn-Banach theorem, the Banach fixed-point theorem, and a half-dozen other concepts that still anchor the field.