Profesor Emérito de Ciencia Política, University of California, San Diego, Estados Unidos.
Entre sus publicaciones destacan: Socialism and Populism in Chile, 1932-52 (University of Illinois Press, 1978); The Money Doctor in the Andes: The Kemmerer Missions, 1923-1933 (Duke University Press, 1989); Labor Movements and Dictatorships: The Southern Cone in Comparative Perspective (Johns Hopkins University Press, 1996) y Between Tyranny and Anarchy: A History of Democracy in Latin America, 1800-2006 (Stanford University Press, 2009).
