Friedrich A. Hayek is generally regarded as the principal intellectual architect of the revival of classical liberalism, as the most effective critic of socialist doctrines, and as one of the preeminent social philosophers of the twentieth century. His life (1899–1992) witnessed all the dramatic episodes of this eventful century, including the eventual collapse of the communist empire. His publications spanned the decades from the early 1920s to the late 1980s, and extended far beyond his original field—economics—into law, politics, philosophy, psychology, and evolutionary theory.