History 184 Social conditions 93 Race relations 78 Governmental investigations 51 African Americans 48 Private investigators 48 Mexican Americans 44 Ethnic relations 42 Motion pictures 42 Police 40 Politics and government 37 General 32 Social life and customs 31 Manners and customs 29 Riots 29 Buildings 28 HISTORY 28 Buildings, structures, etc 27 Economic conditions 24 State & Local 24 Family members 20 Social aspects 20 Immigrants 19 Minorities 19 Description and travel 17 Murder 17 SOCIAL SCIENCE 17 Travel 17 History and criticism 16 Public buildings 16