Book excerpt: "In the early 1990s, a small group of "AIDS denialists," including a University of California professor named Peter Duesberg, argued against virtually the entire medical establishment's consensus that the human immunodeficiency virus (HIV) was the cause of Acquired Immune Deficiency Syndrome. Science thrives on such counterintuitive challenges, but there was no evidence for Duesberg's beliefs, which turned out to be baseless. Once researchers found HIV, doctors and public health officials were able to save countless lives through measures aimed at preventing its transmission"--