Manuel Castells is Professor of Planning at the University of California, Berkeley, and Professor of Sociology and Director of the Institute of Sociology at the University of Madrid.SILVIA FEDERICI is Associate Professor of International Studies and Political Philosophy at New College, Hofstra University. She is a founding member and coordinator of the Committee for Academic Freedom in Africa. Among her earlier publications is Enduring Western Civilization: The Construction of the Concept of Western Civilization (Praeger, 1995).