Oskar Morgenstern (1902–1977) was a Görlitz-born Austrian-German economist who studied under Hans Mayer in Vienna, took his doctorate in 1925, and succeeded Friedrich Hayek as director of the Austrian Institute for Business Cycle Research. Active across nearly every institution of the Austrian School in Vienna, he grew apart from Ludwig von Mises over Mises’s apriorism and his own turn toward mathematics. Removed from his post after the 1938 Anschluss, he emigrated to Princeton, where he and John von Neumann founded the mathematical field of game theory with Theory of Games and Economic Behavior (1944); he later helped found Vienna’s Institute for Advanced Studies in 1963.