G. A. Cohen (1941–2009) was the Chichele Professor of Social and Political Theory at All Souls College, University of Oxford, from 1985 to 2008. At the time of his death, he held the Quain Chair in Jurisprudence at University College London. His books include Karl Marx's Theory of History and Why Not Socialism? (both Princeton). Michael Otsuka is professor of philosophy at University College London.