In the history of modern liberal thought, the work of F.A. Hayek stands out as among the most significant since that of J.S. Mill. In this book, Kukathas critically examines the nature and coherence of Hayek's defense of liberal principles, attempting both to identify its weaknesses and to show why it makes an important contribution to contemporary political theory. Kukathas argues that Hayek's defense of liberalism is unsuccessful because it rests on presuppositions that are philosophically incompatible. In his view, the unresolved dilemma of Hayek's political philosophy is how to mount a systematic defense of liberalism if one emphasizes the limited capacity of human reason. Hayek's social philosophy, he argues, offers a significant theory of the nature of social processes, and is therefore an important account of how this must constrain our choice of political principles.