On 1 October 1995, Steven Epstein published “The Construction of Lay Expertise: AIDS Activism and the Forging of Credibility in the Reform of Clinical Trials,” hereafter “Lay Expertise,” in the journal Science, Technology, & Human Values. In the article, Epstein shows how particular activists in the 1980s helped reform government-run clinical trials for people with acquired immunodeficiency syndrome, or AIDS. Those activists did that work at a time when AIDS was widespread among communities of gay men, and there were no treatments available to combat the disease. Epstein documents how AIDS activists gained credibility in the eyes of the scientific establishment through specific tactics of engagement. “Lay Expertise” laid a foundation for understanding how AIDS movement activism transformed the field of biomedicine, and paved the way for additional research on illness-related social movements, such as those related to infertility and embryonic stem cell research.