History 188 Social conditions 74 Social aspects 40 Race relations 34 Politics and government 33 Ethnic relations 27 Immigrants 23 more ... Mexican Americans 23 Emigration and immigration 19 Motion picture industry 19 Social life and customs 18 Motion pictures 17 African Americans 16 Ethnic identity 16 Indians of North America 16 Economic conditions 14 Community life 13 Education 11 Environmental conditions 11 Minorities 11 Political activity 11 Civil rights 10 Government policy 10 Political aspects 10 Roads 10 Natural history 9 Prevention 9 Water-supply 9 Description and travel 8 Employment 8 less ...