This article is a chapter of my forthcoming book Diversity in America: Keeping Government at a Safe Distance (Harvard U. P., early 2003). book also contains chapters on a conceptualization/taxonomy of diversity (The Diversity of Diversity), an intellectual history of diversity-as-ideal (just published as The Perceived Values of Diversity, Then and Now, 22 Cardozo L. Rev. 1915 (2001)), and chapters analyzing the law and policy governing immigration-related diversity, diversity in residential communities, and religious diversity. There are also introductory and concluding chapters. This article consists of ten sections: (1) an introduction; (2) the definitions, designs, and domains of affirmative action; (3) the importance of context in assessments of affirmative action; (4) the size of affirmative action preferences in different domains, especially higher education; (5) rationales and counter-rationales for ethno-racial preferences (restitution, merit, anti-caste, leadership cadre, market failure, institutional pragmatism, and diversity); (6) the politics of affirmative action (political history, public attitudes, and political survival); (7) the consequences of affirmative action (rate of black progress, distribution of benefits in and outside the favored group, and incidence and distribution of costs); (8) the re-segregation nightmare; (9) alternatives (better targeting within favored groups, disadvantage-based preferences, lottery, addressing root causes, time-limited programs, and voluntary programs); and (10) a conclusion. Prescriptively, I argue that whether or not the diversity rationale for legally-mandated ethno-racial preferences in higher education (and probably elsewhere) can pass constitutional muster (apart from the narrow opening under the Court's Paradise test), public law preferences are unjust and unwise, and are steadily becoming more so. Private preferences, however, are acceptable if the entities using them publicly disclose the nature and magnitude of those preferences and do not discriminate against blacks and other minorities entitled to the highest level of protection under the Constitution.