Steven Epstein's astute and readable investigation focuses on the critical question of "how certainty is constructed or deconstructed," [...] He concludes by analyzing recent moves to democratize biomedicine, arguing that although AIDS activists have set the stage for new challenges to scientific authority, all social movements that seek to democratize expertise face unusual difficulties. Avoiding polemics and accusations, Epstein provides a benchmark account of the AIDS epidemic to date, one that will be as useful to activists, policy makers, and general readers as to sociologists, physicians, and scientists.