The cities of South Africa and Nigeria are reputed to be dangerous, teeming with slums, and dominated by the informal economy but we know little about how people are divided up, categorised and policed. Colonial governments assigned rights and punishments, banned categories considered problematic (delinquents, migrants, single women, street vendors) and give non-state organisations the power to police low-income neighbourhoods. Within this enduring legacy, a tangle of petty arrangements has developed to circumvent exclusion to public places and government offices. In this unpredictable urban reality – which has eluded all planning – individuals and social groups have changed areas of public action through exclusion, violence and negotiation. In combining historical and ethnographic methods, Classify, Exclude, Police explores the effects and limits of public action, and questions the possibility of comparison between cities often perceived as incommensurable. Focusing on state formation, urbanization, and daily lives, Laurent Fourchard addresses debates and controversies in comparative urban studies, history, political science, and urban anthropology. The book provides a systematic, comparative approach to the practices, processes, arrangements used to create boundaries, direct violence, and produce social, racial, gender, and generational differences.