Private and public retirement systems discourage work at older ages. People now retire earlier than they did 50 years ago, even though they are now healthier and work in less physical jobs. Unless older adults work more, the aging of the population will reduce the share of adults that is employed, slow the rate of growth in national output, and strain government's ability to pay for retirement programs and other public services. This report describes how changes to private pensions, Social Security, Medicare, and tax and discrimination law can promote work at older ages.