Harry R. Potter is Associate Professor of Sociology, Purdue University. He has published numerous articles for professional journals, and is presently investigating social change and social structure, and the role of law, citizen participation, and environmental policy in these areas. Dr. Potter#39;s research also includes the decision-making process in the determination of sites for such controversial facilities as toxic waste dumps.Chris Stringer is Head of Human Origins at the Natural History Museum, London.Peter Andrews is the former Head of Human Origins at the Natural History Museum, London.