After two years of study the report of the Workshop on Alternative Energy Strategies (W.A.E.S.) was released in early May 1977 in the fifteen national capitals of the Workshop members. W.A.E.S. is an ad hoc, international project involving 75 individuals from 15 countries. Its objective is to describe a range of feasible alternative energy strategies to the year 2000 for the nations of the World Outside Communist Areas (W.O.C.A.). These 15 countries are major energy consumers, using some 80% of the energy consumed by W.O.C.A. in 1972. Three are also important oil producers and exporters - Iran, Mexico and Venezuela. World oil production is expected to decline before the end of the century under almost any set of world conditions. W.A.E.S. evolved out of the common concern of a number of influential people in various parts of the world who believed that the transition from oil to other energy sources needed to be widely understood and effectively managed in order to avoid major national and international dislocations. The first major task of W.A.E.S. was to identify and agree on the major determinants of future energy supply and demand, to select a range of likely values for these determinants, and to develop a conceptual framework for bringing together the various national and global studies in a way that would be internally consistent, clearly visible and understandable. World energy prices, the rate of world economic growth and national energy policy were selected as the principal determinants of future energy supply and demand to 1985 and to the year 2000. A range of assumptions for each of these key variables was tested and adopted. Specific cases, based on combinations of these principal determinants, were selected to span a wide range of likely future energy supply and demand patterns. 'Scenario' is the term used for each case. A 'scenario' is not a forecast of the future. Rather, it represents a plausible future constructed from certain specified variables. Adding up the estimates of energy demand and supply for W.A.E.S. countries for each 'scenario' of the future, plus estimates for other countries have made it possible to evaluate future world energy balances or imbalances under particular sets of assumptions. The objective of this approach has been to understand better, quantitatively and qualitatively, the major energy issues and choices of the future and to identify which long term strategies will be most useful in balancing future world energy supply and demand. For example, at some point, perhaps before the year 2000, the cumulative national demands for oil imports may well exceed the cumulative potential for oil exports. Years before this happens nations must develop realistic national energy strategies which take account of such a situation. This requires action on a very broad scale, long before such a gap might actually develop, to ensure a smooth transition from energy systems largely based on oil to systems based on other energy sources such as coal and nuclear fuel. The time at which, and the degree to which, the transition from oil to other energy sources is perceived, understood, accepted and acted upon within and among nations will be crucial to an orderly world energy transition. This lecture, which followed the public release of the report, includes a review of the principal conclusions, the methodology used for making supply and demand projections to the year 2000, and some implications for national action and international collaboration.