We have undertaken this volume in the belief that there is now sufficient research completed on environmental risk to justify a retrospective assessment of what is known. Our authors and our intended audience are eclectic indeed. Environ­ mental risk assessment receives increasing attention in the media today. The populace is practically assaulted with stories, with anecdotes, and with conflicting evidence. It is our hope that these chapters will provide the reader with a comprehensive glimpse of a fast-growing field in public policy. No complete survey of the literature would be possible or meaningful. We offer here instead the integrative thoughts of some of the most respected analysts in the field. We believe that the coverage is coherent, the perspectives are illuminating, and the individual "treatments deserving of careful study. We are grateful to Warren Samuels of Michigan State University who is editor of the Kluwer series on recent economic thought. We are also grateful to our Kluwer editor, Zach Rolnik. Both have been gracious in their toleration of unconscionable delays. IX The Social Response to Environmental Risk Policy Formulation in an Age of Uncertainty 1 ENTITLEMENTS AND PUBLIC POLICY IN ENVIRONMENTAL RISKS Daniel W. Bromley* [all rights] are conditional and derivative ... they are derived from the end or purpose of the society in which they exist. They are conditional on being used to the attainment of that end.