This book grew out of the conviction that the preparation and management of large-scale technological projects can be substantially improved. We have witnessed the often unhappy course of societal and political decision making concerning projects such as hazardous chemical installations, novel types of electric power plant or storage sites for solid wastes. This has led us to believe that probabilistic risk analysis, technical reliability analysis and environm, ental impact analysis are necessary but insufficient for making acceptable, and justifiable, social decisions about such projects....