Decades of U.S. nuclear weapons production have exacted a heavy environmental toll. The Department of Energy estimates that cleaning up waste and contamination resulting from production activity will cost over $150 billion. Yet even once that money is spent, these sites will need long-term attention to assure protection of human health and the environment. In the authors' words, stewardship refers to ''institutions, information, and strategies needed to ensure protection of people and the environment, both in the short and the long term,'' after the DOE finishes its ''cleanup'' of the weapons complex. Probst and McGovern make a compelling case for establishing a formal program of long-term stewardship for contaminated sites. The legacy of environmental damage is considerable: hazardous waste disposal, radioactive waste, and contaminated facilities are among the problems that will remain after DOE cleanup efforts are complete. Stewardship planning, they say, must start now. This report details the requirements of a successful stewardship program and discusses the daunting technical and political challenges facing such efforts. It articulates important issues to be tackled, such as the institutional home for key stewardship functions. The authors conclude with suggested next steps.