World War, 1939-1945 1,583 History 1,046 World politics 700 Campaigns 612 Foreign relations 376 Biography 296 World War, 1914-1918 244 Juvenile literature 235 International relations 216 World war, 1939-1945 175 Politics and government 164 Islam 137 Aerial operations 133 Military policy 119 World War 112 Naval operations 107 United States 103 Terrorism 94 Word processing 84 Armed Forces 83 National security 82 Pictorial works 81 Economic conditions 78 English language 78 Airplanes, Military 76 Regimental histories 75 Leadership 72 Secret service 71 War 68 Dictionaries 66