Friedrich August Hayek CH (German pronunciation: [ˈfʁiːdʁɪç ˈaʊ̯ɡʊst ˈhaɪ̯ɛk]) (8 May 1899 – 23 March 1992), born in Austria-Hungary as Friedrich August von Hayek, was an economist and philosopher best known for his defense of classical liberalism and free-market capitalism against socialist and collectivist thought. In 1974, Hayek shared the Nobel Prize in Economics for his "pioneering work in the theory of money and economic fluctuations and... penetrating analysis of the interdependence of economic, social and institutional phenomena."

Hayek is considered to be one of the most important economists and political philosophers of the twentieth century.Along with his mentor Ludwig von Mises, he was an important contributor to the Austrian school of economic thought. Hayek's account of how changing prices communicate information which enable individuals to coordinate their plans is widely regarded as an important achievement in economics.He also contributed to the fields of systems thinking, jurisprudence, neuroscience and the history of ideas.

Hayek served in World War I and said that his experience in the war and his desire to help avoid the mistakes that had led to the war (see below) led him to his career. Hayek lived in Austria, Great Britain, the United States and Germany, and became a British subject in 1938. He spent most of his academic life at the London School of Economics (LSE), the University of Chicago, and the University of Freiburg.

In 1984, he was appointed as a member of the Order of the Companions of Honour by Queen Elizabeth II on the advice of Prime Minister Margaret Thatcher for his "services to the study of economics." He also received the US Presidential Medal of Freedom in 1991 from president George H. W. Bush. In 2011, his article The Use of Knowledge in Society was selected as one of the top 20 articles published in the American Economic Review during its first 100 years.

Bruce J. Caldwell is a historian of economics, Research Professor of Economics at Duke University, and Director of the Center for the History of Political Economy