The opening section of Volume I traces the development of modern thought on the connections between population growth and economic development. The following section looks in particular at the effect of population density on agricultural practices, and the final section deals with population growth and the availability of natural resources.

Volume II opens with a further section on the effects of population density, including its impact on infrastructure and on the size and productivity of cities, and its consequences in the Third World. There follows a brief section on formal theories, including models of technical progress. Finally the determinants of population growth are explored in various studies on the economics of mortality and the correlation between economic conditions and fertility.