The 1992 United Nations Conference on the Environment and Development Earth Summit concluded that the environmental problems of the world's growing urban population need attention; however, the 1993 Ford Foundation-supported evaluation of urban research in developing countries noted that scant data are available on the urban environment, as little research has been done on this topic. Thus, there is a need for environmental action at the local level, but there is little solid information available for building public commitment, planning, and decision making. One solution for resolving this contradiction is to apply the methodology for rapid urban environmental assessment that is developed in this report. The methodology has been explicitly designed to be low cost, rapid, locally managed, and participatory; it is also a possible starting point for environmental planning and management. The first volume in this set is designed for an audience of urban managers, policy makers, analysts, and researchers. It presents the techniques, summarizes results from applying the approach in a selected number of cities, and suggests future directions and improvements. The volume provides: information on the development of the methodology. The second volume details the tools that can be applied in the field by practitioners and researchers. The tools consist of an urban environmental data questionnaire, environmental profile, and guidelines for consultation.