F. A. Hayek (1899-1992), recipient of the Presidential Medal of Freedom in 1991 and cowinner of the Nobel Memorial Prize in Economics in 1974, was a pioneer in monetary theory and a leading proponent of classical liberalism in the twentieth century. Bruce Caldwell is research professor of economics and the director of the Center for the History of Political Economy at Duke University. He is the author or editor of many books, including Hayek's Challenge: An Intellectual Biography of F. A. Hayek, also published by the University of Chicago Press.