The essays in this volume examine the questions of evaluation processes and enforcement with regards to environmental externalities, stressing the role of institutional failures in dealing with the environment. The essays are divided into three sections: 1 - the complexity of evaluation processes; and 3 - evaluation processes and political choice. Overall, the essays argue that the effectiveness of environmental policy depends on the role played by economic institutions in affording and implementing policy objectives. The studies investigates the role played by institutions in affecting and implementing environmental policy. Institutions, in the wider sense, are typically shaped by a complex set of economic and political interests, culture and values which require detailed interdisciplinary analysis.; 2 - the complexity of institutional arrangements