The Americans with Disabilities Act of 1990 was signed into law by President George H.W. Bush on July 26, 1990. The law provides a broad array of civil rights protections for people with disabilities, including prohibitions against employment discrimination and mandates to make public accommodations accessible. The ADA Amendments Act of 2008 expanded the definition of "disability," extending the law's protection to more people. While barriers and discrimination continue to exist (see this article by NYU Law professor Adam M. Samaha for more insight), the ADA has had a profound impact on the ability of people with disabilities to participate in public life.
Above: President Bush signs the ADA into law.
The ADA was enacted in 1990 and amended in 2008. These links will show you the text of the ADA and its legislative history.