As the nation faces the growing aging population, the authors discuss numerous Social Security reform proposals that would scale back benefits, or use individual savings accounts or increased government and Social Security surpluses to try to increase national saving and, eventually, to replace lost benefits. The authors conclude that proposals should be judged according to their ability to meet various goals or principles. Among the most important are fairness, economic efficiency, and economic growth. More research is needed on the fine points of proposals to fend off a retirement crisis and put Social Security and Medicare on a secure footing. Such research should feed into a national dialogue on Americans' shared retirement future.