The Stewart B. McKinney Homeless Assistance Act (P. L. 100-77) of 1987 was the first major federal legislation enacted to address the welfare of America's homeless population and remains to this day the only such effort. This legislation marked a significant departure from the traditionally indifferent federal stance on the issue. This paper explores the question: Why did homelessness emerge as a major social problem in 1987 and not before? As this paper reveals, the development of homelessness as a public issue was predicated on a fundamental redefinition of what being homeless meant and who was to blame. Extensive advocacy efforts, key legal precedents, the media, and concentrated lobbying efforts all catalyzed this process and challenged policy makers to rethink some long-held misconceptions about the homeless. The end result was a somewhat comprehensive (though also limited) federal response in the form of the McKinney Act.