In nearly every industrialized country, large aging populations and increased life expectancy have placed enormous pressure on social security programs-and, until recently, the pressure has been compounded by a trend toward retirement at an earlier age. With a larger fraction of the population receiving benefits, in coming decades social security in many countries may have to be reformed in order to remain financially viable. This volume offers a cross-country analysis of the effects of disability insurance programs on labor force participation by older workers. Drawing on measures of health that are comparable across countries, the authors explore the extent to which differences in the labor force are determined by disability insurance programs and to what extent disability insurance reforms are prompted by the circumstances of a country's elderly population.