The history of policing in America cities since the colonial period has been shaped by the country's distinctive legal culture and political traditions (leading to fragmented, local control), by power struggles of class, ethnicity, and race (leading to corrupt, unequal, and often abusive policing), but also by cycles of reform (leading to distinct eras of policing styles). Urban policing has both reflected larger historical forces and trends-including industrialization, demographic change, capitalist transformation-and become one itself, shaping the outcomes of social conflict and much of the daily lives of city residents. Technological change, likewise, has remade both the legal relationship between citizens and law enforcement and the supervisory relationship between police officers and police administrators. Awareness of this broader history underscores the malleability of seemingly fixed cultural concepts-notably those of race, rights, and resistance-as well as highlights the possibility and limits of efforts to reform American policing.