The links between population growth, resource use, and environmental quality are too complex to permit straightforward generalizations about causal relationships. However, rapid population growth has increased the number of poor people in developing countries, thus contributing to the degradation of the environment and the renewable resources of land, water, and nonhuman species on which humans depend. Demands of the rich industrial countries have also generated environmental pressures; the developed nations have been foremost in consumption of the nonrenewable resources of fossil fuels, metals, and nonmetallic minerals. On the other hand, population and economic growth have also stimulated technological and management changes that help supply and use resources more effectively. Wide variations in the possible ultimate size of world population and accelerating technological change make future interrelationships of population, resources, and the environment uncertain as well as complex. But those interrelationships are mediated largely by government policies. Responsible governments can bring about a sustainable balance in the population/resource/environment equation by adopting population and development policies that experience has shown could reduce future population numbers below the additional five billion projected by the United Nations for the close of the twenty-first century, coupled with proven management programs in both developing and developed countries that could brake and reverse the depletion and degradation of natural resources. Sixty-nine references and 12 tables are provided. (AEM)