In the second half of the twentieth century, no one had more influence over Social Security than Robert Ball, who in 1947 wrote the key statement defining why social insurance, not welfare, should be America's primary income maintenance program. Drawing on exclusive access to Ball's papers and Ball's own extensive oral memoir created for this project, Edward D. Berkowitz explains how Social Security came to be America's most important social welfare program. Ball's role in expanding coverage to more workers, as well as in supporting the indexing of benefits to the rate of inflation, directly affected the lives of senior citizens and the overall U. S. economy. Finally, Berkowitz considers Ball's legacy in the face of the George W. Bush administation's goal of replacing Social Security with private accounts.