William Clark is the Harvey Brooks Professor of International Science, Public Policy and Human Development at Harvard University's John F. Kennedy School of Government.  Trained as an ecologist, his research focuses on the interactions of environment, development and health concerns in international affairs.  At Harvard, he currently co-directs the Sustainability Science Program.  He is co-author of Adaptive environmental assessment and management (Wiley, 1978), and Redesigning rural development (Hopkins, 1982); editor of the Carbon dioxide review (Oxford, 1982); coeditor of Sustainable development of the biosphere (Cambridge, 1986), The earth transformed by human action (Cambridge, 1990), Learning to manage global environmental risks (MIT, 2001), Global Environmental Assessments (MIT, 2006) and The global health system: Institutions in a time of transition (Harvard, 2010);  and co-chair of the US National Research Council's study Our Common Journey: A Transition Toward Sustainability (NAP, 1999).  He serves on the editorial board of the Proceedings of the National Academy of Science.  Clark is a member of the National Academy of Sciences and a Fellow of the American Association for the Advancement of Science.  He is a recipient of the MacArthur Prize, the Humboldt Prize, the Kennedy School's Carballo Award for excellence in teaching, and the Harvard College Phi Beta Kappa Prize for Excellence in Teaching.