The private seminars that Mises held, and which were so successful in Vienna beginning in 1919, were actually separate from the University. Mises here remembers many of his seminar participants, like Hayek, Haberler, Schutz, and Machlup. He was glad to have contributed to the development of international cooperation among so many economists.
Ludwig von Mises was the acknowledged leader of the Austrian school of economic thought, a prodigious originator in economic theory, and a prolific author. Mises's writings and lectures encompassed economic theory, history, epistemology, government, and political philosophy. His contributions to economic theory include important clarifications on the quantity theory of money, the theory of the trade cycle, the integration of monetary theory with economic theory in general, and a demonstration that socialism must fail because it cannot solve the problem of economic calculation. Mises was the first scholar to recognize that economics is part of a larger science in human action, a science that he called praxeology.