This is Ludwig von Mises's magnum opus, the magisterial contribution in which he develops his flagrantly controversial philosophy of the social sciences, his brilliant entrepreneurial theory of the market process, and his devastatingly consistent classical liberal perspective on political economy, into an overarching system of extraordinarily impressive scope. Human Action is a work that has, for almost half a century, retained its freshness and its relevance, showing how deep economic understanding is to be attained, not by virtuosity of mathematical technique, but by subtlety and penetration of economic insight and interpretation. Recent developments in the economics profession suggest that the most far-reaching impact upon economic thought exerted by this celebrated work may be that still to come. -- Israel M. Kirzner, New York University, author Competition and Entrepreneurship