World War, 1939-1945 1,583 Campaigns 547 History 535 Biography 182 World war, 1939-1945 175 Aerial operations 116 World War 96 Naval operations 95 Regimental histories 71 Secret service 66 Aerial operations, British 59 Tank warfare 54 Personal narratives 52 Equipment and supplies 49 Personal narratives, British 47 Germany 46 History, Military 44 Naval operations, American 44 Personal narratives, American 43 Submarine 43 Foreign relations 41 Causes 37 Juvenile literature 37 Aerial operations, American 36 United States 36 Pictorial works 35 Military intelligence 34 Great Britain 33 World War, 1914-1918 33 Diplomatic history 32