History 2,285 Politics and government 1,489 Foreign relations 873 World politics 545 Biography 490 World War, 1939-1945 322 Economic conditions 308 United States 247 Social conditions 190 Islam 188 Campaigns 181 Military policy 173 Economic policy 152 History, Military 147 National security 133 Juvenile literature 125 Armed Forces 121 Military art and science 117 Military history, Modern 102 Terrorism 102 World War 102 International relations 98 Congresses 86 Presidents 84 Great Britain 81 Political activity 68 Cold War 67 Communism 65 World War, 1914-1918 62 Fiction 60