Friedrich August von Hayek CH was an Austrian and British economist and philosopher known for his defense of classical liberalism and free-market capitalism against socialist and collectivist thought. He is considered by some to be one of the most important economists and political philosophers of the twentieth century. Hayek's account of how changing prices communicate signals which enable individuals to coordinate their plans is widely regarded as an important achievement in economics. Hayek also wrote on the topics of jurisprudence, neuroscience and the history of ideas. Hayek is one of the most influential members of the Austrian School of economics, and in 1974 shared the Nobel Memorial Prize in Economics with Gunnar Myrdal "for their pioneering work in the theory of money and economic fluctuations and for their penetrating analysis of the interdependence of economic, social and institutional phenomena." He also received the U.S. Presidential Medal of Freedom in 1991 from president George H. W. Bush. Hayek lived in Austria, Great Britain, the United States and Germany, and became a British subject in 1938.