Abstract: Papers, 1935-2007, of Robert Ball, a career official and commissioner of the Social Security Administration (SSA), who guided the development of the social security system from 1962 to 1973. As commissioner, Ball presided over several reorganizations of the SSA, major expansions of benefits, and the passage of the Medicare Act in 1965, and also served as a member of a number of Advisory Councils for Social Security (1938-1997) and of the President's National Commission on Social Security Reform, which led to a number of amendments to the Social Security Act in 1983. The papers primarily document Ball's career in the SSA, but also concern his many other social insurance and social welfare policy-related activities.