This paper, one of a series published by the Worldwatch Institute to identify and focus attention on global problems, is adapted from the author's book, "Rays of Hope: The Transition to a Post-Petroleum World." The author examines the current energy problems of the world, and determines that the energy patterns of the past are not the prologue to the future. The inadequacies associated with energy alternatives to petroleum, such as coal and nuclear fusion, are identified and discussed. Thus, society is left with only the solar options: wind, falling water, biomass, and direct sunlight. The historical development, technology, and current status of each of the solar options is detailed. The social and political ramifications of the conversion to a society based on solar energy are hypothesized. The author concludes that the conversion to solar energy is technically feasible, economically sound, and environmentally attractive. (BT)