Economic aspects History 674 Economic conditions 306 Social aspects 268 Agriculture 193 Government policy 152 Finance 139 more ... Political aspects 135 Technological innovations 125 Emigration and immigration 109 Education, Higher 106 Education 104 Law and legislation 103 Social conditions 94 Economic policy 90 Slavery 83 Globalization 81 Politics and government 78 Environmental aspects 58 Environmental policy 57 Race relations 57 Universities and colleges 56 World War, 1939-1945 56 Taxation 52 Agriculture and state 51 Commerce 51 African Americans 48 Foreign relations 48 Income distribution 47 Management 46 less ...