The rapid growth of American cities has brought about an urban society with major problems of congestion, pollution, poverty and crime.- Successful planning for the form and patterns of cities requires reliable methods for anticipating the future. The complexity of cities provides a major technical barrier to the anticipation of the future of cities. The increasing diversity of social goals creates cultural and political barriers to effective planning. During the last decade, a major body of literature has emerged outlining alternative futures for American society. A review of major studies of the future provides a set of divergent societal contexts which place realistic boundaries on the future prospects. The major issues discussed are population growth, economic growth, energy supply, waste absorption capacity, mechanisms of social control, the gap between the rich and poor, and psychological adjustment to change. Resolutions to the major issues are combined into scenarios of optimism, pessimism, and transformation which have major implications for cities. Existing theories in the areas of transportation and urban growth, neighborhoods and land-use districts, and housing, provide a way to convert the alternative scenarios into detailed implications for urban form. Cause and effect relationships have been documented which make linkages between cities and the larger societal context. The relationships are used to generate alternative scenarios of urban form. The scenario of optimism leads to the continued prosperity and growth of cities. Urban form continues to become less concentrated as transportation problems are solved through the combination of technological breakthroughs and affluence. The scenario of pessimism is based on energy shortages and a colder climate. Mass migration, high unemployment, makeshift housing, and the scavenging of buildings for fuel and construction materials are likely. The scenario of transformation involves evolution to a "steady state" society. Many cities are expected to remain stable in population or to decline. Population growth is anticipated in smaller cities: energy conservation is emphasized; and new social structures are developed to achieve personal freedom within the limits imposed by natural scarcities. Explorations of all scenarios are needed to increase public awareness of the future, and to assist in the assessment of the likelihoods of the different scenarios. Currently, transformation is emerging as the dominant scenario. It offers the best opportunity for survival, for maintaining a high standard of living, and for increasing personal freedom. Planning for transformation is the appropriate strategy for addressing current problems of urban form.