Mark Kac (pronounced kahts, Polish: Marek Kac, Ukrainian: ????? ???, b. 3 August 1914, Krzemieniec, Russian Empire, now in Ukraine; d. 26 October 1984, California, USA) was a Polish mathematician. His main interest was probability theory. His question, "Can you hear the shape of a drum?" set off research into spectral theory, with the idea of understanding the extent to which the spectrum allows one to read back the geometry. (In the end, the answer was "no", in general.)
Kac completed his Ph.D. in mathematics at the Polish Jan Kazimierz University of Lwów in 1937 under the direction of Hugo Steinhaus. While there, he was a member of the Lwów School of Mathematics (pol. Lwowska Szko?a Matematyczna). After receiving his degree he began to look for a position abroad, and in 1938 was granted a scholarship from the Parnas Foundation which enabled him to go work in the United States. He arrived in New York City in November, 1938. From 1939 until 1961 he was at Cornell University, first as an instructor, then from 1943 as assistant professor and from 1947 as full professor. While there, he became a naturalized US citizen in 1943. In 1961 he left Cornell and went to Rockefeller University in New York City. After twenty years there, he moved to the University of Southern California where he spent the rest of his career.
Mark Kac and Stanis?aw Ulam: Mathematics and Logic: Retrospect and Prospects, Praeger, New York (1968) Dover paperback reprint.
Mark Kac, Enigmas of Chance: An Autobiography, Harper and Row, New York, 1985. Sloan Foundation Series. Published posthumously with a memoriam note by Gian-Carlo Rota. Kac's distinction between an "ordinary genius" like Hans Bethe and a "magician" like Richard Feynman has been widely quoted. (Kac knew both at Cornell University.)