Friedrich August von Hayek (1899-1992) is undoubtedly one of the most significant liberal thinkers of the past century. Born and raised in Vienna in the tradition of the Austrian School, he held academic positions i.a. in London, Chicago and Freiburg, thus uniting in his vita the four principal centers of neo-liberalism. His intellectual development is of special interest, since he shifts the focus of his research agenda several times, most notably from the field of business cycle research towards the broader field of social philosophy. According to this well-known break in his oeuvre, there is a classical division in secondary literature, splitting him into the two phases: Hayek I (the business cycle theorist) and Hayek II (the social philosopher). The present paper will try to show that this two-fold division is inadequate, or at least incomplete. Instead, a three-fold division seems more appropriate: here, Hayek I would again be the business cycle theorist, but Hayek II is seen as an ordo-liberal philosopher and Hayek III as the evolutionist philosopher. Regarding the time-span of the latter phases, the paper contends that the ordoliberal Hayek is to be seen in the 1930s and 1940s (the time of The Road to Serfdom and the founding of the Mont Pèlerin Society), whereas his evolutionist phase starts in the 1950s and continues to the end of his life.
