Experts on population research here team with economists, applying the techniques of economic analysis to demographic material. The interrelationship of demographic and economic changes in industrially advanced countries-Europe except Iberia and the Balkans, Oceania, North America, Japan, and the Soviet Union-is assessed, with emphasis upon fertility variations as determinants of change since mortality differences are relatively slight. Variables in fertility affecting the labor force are evaluated, and show that the number of women entering the labor force involves a country's whole economic structure.