This article reviews the major legislative initiatives outlawing discrimination, discusses the theoretical arguments for and against such initiatives, and assesses the impact of these laws on the groups they try to protect. The significant effects of federal law in the first decade after passage of the 1964 Civil Rights Act are contrasted with the less optimistic findings from subsequent anti-discrimination interventions. Insights about the social benefits and the costs of the unintended consequences of employment discrimination law apply equally to other types of anti-discrimination legislation, such as mortgage lending and policing.