In the two decades following the appearance of the American Psychiatric Association's catalogue of mental illnesses, male homosexuality changed from a sexual deviation listed among other serious personality disorders (1952) to no disorder at all--a ""sexual orientation disturbance"" only for those in conflict with that orientation (1973). Why the change? Had the APA capitulated to angry outside demonstrators, as some charged, or did a process of scientific re-evaluation take place? And did the nomenclature change truly represent the convictions of practicing psychiatrists? Ronald Bayer, a policy studies specialist, has untangled the twisty, blurry lines of this peculiar sequence of events with consummate skill. Much of the work, he demonstrates, was initiated by informed gay activists (Voeller, Kameny, Gold) in sometime contact with a small circle of psychiatrists committed to re-appraising the issue. These psychiatrists, Marmor and Spitzer most prominently, became convinced that the orthodox writings of Bieber and Socarides were insupportable, that the label ""mental disorder"" (which had once protected gays from criminal prosecution) was in fact unwarranted and served, indefensibly, as the basis for widespread discrimination--by the armed forces, employers, housing projects, the Immigration Department, etc. At the same time, public attitudes toward the civil rights of minorities had shifted, and concepts of illness had been revised: value judgments and other subjective criteria had been recognized in scientific disciplines. Bayer suggests that psychiatrists, usually insulated from theoretical matters, were forced by organized challengers to re-examine the evidence. Despite many sharp professional disagreements, the APA membership was able to acknowledge that the designation was questionable and that the list of gay grievances had merit--hence the 1973 referendum which supported deletion of homosexuality from the ""disorders"" classification. The change in nomenclature, still controversial within the APA, has resulted in some civil rights gains in American society but not the broad social legitimation which gays sought. Moreover, Bayer believes that, given the outside influences still at work, the 1973 decision remains quite vulnerable, especially in the more conservative present. An exemplary nonpartisan investigation, faithful to detail, focused on larger themes, and wholly acceptable to a broad audience--straight, gay, or APA.