Nineteenth century histories of American law enforcement have a progressive perspective that dismisses or overlooks racial, ethnic, and class distinctions and conflicts in assuming homogeneity and consensus in the social order. The police are viewed as representatives and defenders of American institutions and values threatened by criminals and anarchists. These histories are theoretically and methodologically simplistic and at times historically inaccurate. Radical-Marxist historians offer an opposing view of the history of American law enforcement as they view America's social order as essentially heterogeneous, with various groups competing for power and, most importantly, economic advantage. Radical-Marxists see the police as the oppressive arm of the capitalists in their efforts to increase profits and economic domination at the expense of the working class. Critics of radical-Marxist research methods claim they are reductionist because of an overemphasis on historical materialism and class conflict. Although social context theorists share radical historians' views on the need to relate law enforcement development to changing conditions in the social structure, they reject the radical historians' emphasis on economic determinism and opt for a wider vision of the significant components of the social structure. Their historical studies tend to focus on the environmental dynamics that molded the development of police departments in specific urban areas. The weakness of their studies has been a failure to generalize from the historical studies of particular departments. In the future, police historians should use more advanced historiographic methods; a priori assumptions, methodology, analytical biases, and theoretical orientation should be explicitly stated, and an effort should be made to study a variety of police agencies in a comparative setting and in relation to other agencies of social control. A total of 105 footnotes is provided.