Foreign relations 150 History 100 Politics and government 98 Social conditions 50 Economic conditions 47 Civilization 38 World politics 29 Popular culture 22 Social aspects 20 Cold War 19 Addresses, essays, lectures 16 Presidents 13 Social movements 12 Social life and customs 10 Vietnam War, 1961-1975 10 Vietnamese Conflict, 1961-1975 10 Economic policy 9 Counterculture 8 Economic aspects 8 Intellectual life 8 Political activity 8 International relations 7 Protest movements 7 Radicalism 7 Social change 7 Case studies 6 Civil rights 6 Nineteen sixties 6 Political activism 6 Public opinion 6