Mark Sagoff is Interim Director and Senior Research Scholar at the Institute for Philosophy and Public Policy in the School of Public Policy at the University of Maryland, College Park.  He has published widely in journals of law, philosophy, and the environ­ment.  His books include The Economy of the Earth (Cambridge University Press, 1988) and Price, Principle, and the Environment (Cambridge University Press, 2004).  He was named a Pew Scholar in Conservation and the Environment in 1991 and awarded a Fellowship at the Woodrow Wilson International Center for Scholars in 1998.   He is a fellow of the Hastings Center and of the American Association for the Advancement of Science. Sagoff has an A.B. from Harvard and a Ph.D. (Philosophy) from Rochester, and he taught at Princeton, the Uni­ver­sity of Pennsylvania, the University of Wisconsin (Madison), and Cornell before coming to the University of Maryland.