A systematic discussion of the consequences of rapid population growth for economics and social systems examines growth resulting from mortality decline in the absence of comparable fertility decline. Growth resulting from net migration is also considered. The background and rationale for the study are supplied in a brief introduction. Part 2 discusses the demography of rapid population growth in terms of effects on population size, age structure, kinship frequencies, and social group composition. Part 3 investigates population growth effects on the economy, chiefly its effects on technological change, capital formation, and labor absorption. Part 4 briefly explores the consequences for social and political organizations, administrative systems, and international consequences. Part 5 examines individual-level and distributional consequences. The final section considers some of the issues involved in valuing alternative population growth trajectories, given agreement on the factual implications of growth for the economy and society in a particular setting. (Author/RSL)