Planning, operating, and policy making in the electric utility and natural gas sectors involves important trade-offs among economic, social, and environmental criteria. These trade-offs figure prominently in ongoing debates about how to meet growing energy demands and how to restructure the world's power industry. This work reviews practical tools for multicriteria (also called multiobjective) decision analysis that can be used to quantify trade-offs and contribute to more consistent, informed, and transparent decision making. These methods are designed to generate and effectively communicate information about trade-offs; to help people form, articulate, and apply value judgments in decision making; and to promote effective negotiation among stakeholders with competing interests. The text includes explanations of a wide range of methods, tutorial applications that readers can duplicate, a detailed review of energy-environment applications, and three in-depth case studies.