Edward D. Berkowitz and Larry DeWitt have spent their careers honing a portrait of the centerpiece of the New Deal welfare state—the Social Security Act. Together, they have pulled its previously unknown architects into the limelight, illuminated lesser-known elements of the system, drawn connections to insurance expansions like disability and Medicare, and provided scholars and students with access to primary sources crucial to its historical development. From DeWitt's position as chief historian of the Social Security Administration and Berkowitz's perch as professor of history and public policy and public administration at George Washington University in Washington, D.C., they have modeled generous, cooperative scholarship. In their second collaboration, they bring their knowledge and experience to bear on a distant relation of Social Security in a much later period—the Supplemental Security Income Program (SSI). In the last quarter of the twentieth century, SSI emerged as a large, vital component of the welfare state, but its history, nevertheless, has been little-understood. SSI is a means-tested income-support program for the elderly and disabled who are not otherwise eligible for the larger federal disability insurance program, Social Security Disability Insurance. Created in 1972, SSI has come to serve over nine million Americans and continues to grow annually. Its architects in the Social Security Administration and Congress intended to include elderly and disabled adults as part of a more respectable, federally controlled welfare program—one more generous and more uniform than the previous Old Age Assistance program or the despised Aid to Families with Dependent Children, serving single mothers. In practice, however, the program fell short of those goals. Berkowitz and DeWitt demonstrate how SSI quickly evolved into a system as variable, vulnerable, and unpopular as many of the other means-tested “welfare” programs. Though policymakers desired a truly national program, compromises in the legislative and administrative processes left SSI at the mercy of state and congressional meddling. SSI paid radically different benefits from state to state as a result. The authors also track how shifting target populations generated hostility from lawmakers and the media. Though SSI initially aimed to provide support to the “respectable” elderly and disabled, increasing numbers of mentally disabled, mentally ill, and addicted adults and children soon populated the program. None of them proved to be popular or politically influential clientele. From the moment of the program's birth through the 1990s, journalists and disgruntled members of Congress attacked SSI's recipients. Today, despite the aims of its architects, SSI hovers just above Temporary Assistance for Needy Families and the food stamp program in the eyes of its critics.