World War, 1914-1918 History 215 Foreign relations 66 Politics and government 53 Campaigns 49 International relations 49 Economic aspects 45 more ... World War, 1939-1945 43 Regimental histories 38 Social aspects 31 Military campaigns 30 Women 30 Diplomatic history 28 Social conditions 28 Armed Forces 25 History and criticism 24 African Americans 22 Literature and the war 22 Influence 19 Neutrality 19 Soldiers 19 Finance 17 Propaganda 15 Public opinion 15 Peace 14 Economic conditions 13 History, Military 13 Aerial operations, American 12 War 12 Argonne, Battle of the, France, 1918 11 less ...