Ángel Rivero is Professor at the Department of Politics and International Relations of the Universidad Autónoma de Madrid (UAM), where he teaches political theory. He received his PhD in Philosophy from UAM and his BSc in Social Sciences with Politics and Sociology from the Open University, UK. He is recurring Visiting Professor at several universities in Latin America, and was Fulbright Visiting Scholar at the Graduate Faculty of Political and Social Science at the New School for Social Research, New York, where he worked with Ágnes Heller. His interests range widely in political philosophy, political ideologies, and theories of nationalism. Professor Rivero served as Head of the Department of Politics and International Relations at UAM from 2000 to 2003, and was co-director of the Master’s Program on Portuguese Studies at the same university. His most recent book is The Constitution of the Nation (in Spanish, 2011), which received the 1808 Bicentenary Prize.Ángel Prior is Professor at the Department of Philosophy of the University of Murcia, having formerly worked at the University of Valencia, where he received his BA and PhD degrees. He has published widely on classical Marxism and the New Left, and has dedicated many articles and books to the work of Hannah Arendt and, above all, to the work of Ágnes Heller. His most recent books are The Two Pillars of Modern Ethics: Dialogues with Ágnes Heller (edited with Ángel Rivero, in Spanish, 2008) and Will and Accountability in Hannah Arendt (in Spanish, 2009).