World War, 1939-1945 Campaigns 33 History 26 Aerial operations 10 Equipment and supplies 5 Secret service 5 Aerial operations, British 4 Naval operations 4 Armed Forces 3 Biography 3 Cryptography 3 History, Military 3 Regimental histories 3 United States 3 Western Front 3 World War 3 World War, 1914-1918 3 Aerial operations, American 2 Causes 2 Diplomatic history 2 Foreign relations 2 Germany 2 Great Britain 2 Military intelligence 2 Naval Operations 2 Normandy (France) 2 Ordnance and ordnance stores 2 Personal narratives, American 2 Personal narratives, British 2 Siege, 1942 2