Like F.A. Hayek, Ludwig von Mises moved beyond economics in his later years to address questions regarding the foundation of all social science. But unlike Hayek's attempts, Mises's writings on these matters have received less attention than they deserve. Theory and History, writes Rothbard in his introduction, "remains by far the most neglected masterwork of Mises."Here Mises defends his all-important idea of methodological dualism: one approach to the hard sciences and another for the social sciences. He defends the epistemological status of economic proposition. He has his most extended analysis of those who want to claim that there is more than one logical structure by which we think about reality. He grapples with the problem of determinism and free will. He presents philosophy of history and historical research. Overall, this is a tremendously lucid defense of the fundamental Misesian approach to social philosophy.