Friedrch August von Hayek (1899-1992) was undoubtedly one of the most consequential political thinkers in the twentieth century. He influenced policy makers such as Margaret Thatcher and Ronald Reagan, as well as leading economists such as Milton Friedman, whose legacy lives on and thrives in the Chicago School of Economics. Recently, his work has become the object of increased scholarly interest. The University of Chicago Press is publishing an edition of his collected writings, and no less than four biographies have appeared in print since the year 2000, in addition to more specific monographs on Hayek’s social, economic and political philosophy. However, the new wave of studies has paid relatively little attention to the central role of evolutionary considerations in Hayek’s thought. It is this lacuna that my book seeks to fill. A close look at Hayek’s use of evolutionary ideas is likely to provide new insights concerning the old, so-called “social Darwinist” question, a misnomer for the question of the relationship between evolutionary biology and politics. In my study I propose, on the one hand, to investigate Hayek’s claims with reference to past developments of similar vein (e.g. Herbert Spencer) and compare them with those of his good friend, Karl Popper, and with Darwin’s. I intend, in this way, to highlight the problematic aspects of the parallels Hayek drew between economics and evolutionary biology. On the other hand, I will emphasise Hayek’s modernity and the originality of his contributions to the ongoing debate on the meaning of evolution in the social, political and ethical realms. I will analyse, for instance, his developments in theoretical psychology, e.g. neural network modelling, and relate them to the work of modern evolutionary psychologists. I will also examine Hayek’s theory of group selection, the corner stone in his project to give evolutionary interpretation of the growth of human civilisation, and the object of heated controversies in socio-biology today. Finally, I will examine Hayek’s attempt to assign normative content to the outcome of social evolution and explore his extensive use of biological analogies in support of what he termed “the liberal society.” I will challenge Hayek’s interpretation of natural development to see whether it bears out the weight of his staunch attack on socialist reforms and is able to buttress his free market politics.