This volume analyzes the changing economic and demographic environment in which social insurance programs benefiting elderly households will operate. It also explores how these ongoing trends will affect future beneficiaries, under both the current Social Security program and potential reform options. An esteemed group of economists probes the challenge posed to Social Security by an aging population. The researchers examine trends in private sector retirement saving and health care costs, as well as the uncertain nature of future demographic, economic, and social trends - including marriage and divorce rates and female participation in the labor force. Recognizing the ambiguity of the environment in which the Social Security system must operate and evolve, this landmark book explores factors that policy makers must consider in designing policies that are resilient enough to survive in an economically and demographically uncertain society.