This volume consists of papers presented at a conference held in Carefree, Arizona, in May 2003. Most of the research was conducted as part of the program on the Economics of Aging at the National Bureau of Economic Research. The majority of the work was sponsored by the U.S. Department of Health and Human Services, through the National Institute on Aging grants P01-AG05842 and P30-AG12810 to the National Bureau of Economic Research. Any other funding sources are noted in the individual papers.