History 524 World War, 1939-1945 369 Campaigns 151 Politics and government 148 Biography 117 Description and travel 80 Aerial operations 51 Foreign relations 47 World War, 1914-1918 44 Vietnamese Conflict, 1961-1975 41 Encyclopedias 40 Civilization 38 Dictionaries 38 Guidebooks 38 Pictorial works 34 Juvenile literature 33 World war, 1939-1945 27 Economic conditions 25 Maps 24 Social conditions 22 History, Military 21 Naval operations 18 Geography 17 World War 17 World politics 17 Battles 16 Naval operations, American 16 Armed Forces 15 Causes 15 Malaysia 15