Carl Menger (1840–1921) was an influential thinker and professor at the University of Vienna. His Principles of Economics of 1871 was a breakthrough in economic theory, notably for its marginalist approach and its subjectivist approach to value. His individual-centered conception of the economy was soon perceived as revolutionary and has ever since attracted generations of scholars to expand on this conception, with his immediate and closest associates being Eugen von Böhm-Bawerk (1851–1914) and Friedrich von Wieser (1851–1926). Following the publication of his Investigations into the Method of the Social Sciences with Special Reference to Economics in 1883, Menger engaged in what later would become known as the Methodenstreit, a controversy which, among others, addressed the relative roles of theory and history in economics. His principal opponent was the head of the Younger Historical School, Gustav Schmoller (1838–1917). In the decades after the Methodenstreit, Menger remained influential, both as teacher and as a public figure, but did not publish any new treatises. After the birth of his son Karl in 1902, Menger increasingly withdrew from public life, and Wieser succeeded him at the University of Vienna as the professor of economic theory. After his death, his partner Hermine Andermann sold his library to Hitotsubashi University in Japan. His archives are preserved at Duke University. Between 1933 and 1936, Friedrich A. Hayek edited the four-volume Collected Works of Carl Menger. Menger is widely credited as one of the founders of the Austrian School of economics.