Established in 1974, SSI provides cash assistance to older adults and/or individuals with disabilities who have low income and few assets.  Currently, about 60 percent of SSI recipients are adults with disabilities (ages 18 to 64), about 15 percent are disabled children (under age 18), and about 25 percent are older adults (age 65 or over) with or without disabilities. The report discusses how the SSI program works, who receives payments, the program’s spending, and its interaction with other government programs, the extent to which SSI affects people’s work and saving, and possible approaches to changing the program.