Jens Meierhenrich is Associate Professor of International Relations at the London School of Economics and Political Science His books include Genocide: A Very Short Introduction and Genocide: A Reader (both forthcoming from Oxford University Press in 2014). Ernst Fraenkel (1898--1975) was an eminent political scientist who began his professional career as a labor lawyer in Weimar Germany. Forced to flee the Nazi dictatorship in 1938, he emigrated to the United States and worked as an adviser to the U.S. government. Fraenkel returned to Germany in 1951, where, as a professor at Berlins Freie Universität, he played a leading role in establishing the discipline of political science in the country of his birth.