World War, 1939-1945 Campaigns 63 History 47 Biography 26 Secret service 12 Personal narratives, British 10 World War, 1914-1918 9 Aerial operations 8 Generals 8 Regimental histories 8 Aerial operations, British 7 Diplomatic history 7 Foreign relations 7 Naval operations 6 Juvenile literature 5 Siege, 1942 - 5 Underground movements 5 War 5 Cryptography 4 History, Military 4 Japanese occupation 4 Military leadership 4 Prisoners and prisons, Japanese 4 Soldiers 4 Equipment and supplies 3 Military history, Modern 3 Naval operations, British 3 Personal narratives, American 3 Personal narratives, Australian 3 Personal narratives, German 3