The Institute of Ecology (TIE) was organized to provide a mech anism for addressing ecological and environmental issues that were beyond the special interests of ecology as a profession. One method of evaluating such issues is the workshop, and this report describes the results of the third TIE workshop on a major environmental subject. The ecology of tropical regions is of interest to all the inhabitants of the biosphere. The tropics provide mankind with both the opportunity for and the challenge of essential resources, land for settlement and development, and waters for numerous uses. Moreover, they provide examples of misuse of the landscape, fragility of ecological systems, and serious environmental problems. Unfortunately, the study of the ecology of the tropics has not kept pace with the ecology of other regions. The purpose of this report, therefore, is to determine the research approaches that will lead to advances in our theoretical un derstanding of tropical systems and, more importantly, in the applica tion of that knowledge to human problems. Although the principal focus of the report is on the neotropics, it will be useful to the full spectrum of persons concerned with the tropics around the world government officials, sCientists, students of ecology, and others. TIE is especially pleased to thank the numerous scientists and ad ministrators who participated in the workshop and who contributed to this report. Arthur D.