The lecture notes presented in these pages were originally developed for use in the Energy Management Training Program (EMTP), sponsored by the Office of Energy, U. S. Agency for International Development. This program, held at Brookhaven National Laboratory (BNL) and the Institute for Energy Research, State University of New York at Stony Brook, is designed to train mid-career and senior government officials in developing countries in the techniques of energy policy analysis and planning, and covers, in addition to the material presented here, more detailed case studies in resource evaluation, pricing, conservation, financial analysis, and investment planning. Since its incepΒ tion in 1978, some 220 individuals from 57 countries have attended the course. These notes have also been used in executive level seminars and inΒ country training programs in the Sudan, the Dominican Republic, and the People's Republic of China. Attendance at the course is diverse, and typically includes planners, managers, engineers, and economists from energy planning agencies, ministries of finance and economic development, electric utilities, refineries and State Oil Companies, and specialized energy planning units for energy conservation and for regional cooperation. The monograph is designed not just as reading material to support lectures, but also as a general self-contained reference text for a very diverse audience: we have therefore included much introducΒ tory material. The presentation is focused on a discussion of the basic principles of systems analysis: and the case material has been specially designed to illustrate these principles.