In nearly every industrialized country, large aging populations and increased life expectancy have placed pressure on social security programs - and, until recently, the pressure has been compounded by a trend toward retirement at an earlier age. As such, social security in many countries may soon have to be reformed in order to remain viable. This volume offers an analysis of the effects of disability insurance programs on labor force participation by older workers. Drawing on measures of health comparable across countries, it explores how differences in the labor force are determined by disability insurance programs and to what extent reforms are prompted by the circumstances of a country's elderly.