20th century History 17 Naval history, Modern 6 Naval art and science 4 Politics and government 4 Biography 3 Sailors 3 Foreign relations 2 Military history, Modern 2 Political and government 2 World War, 1914-1918 2 World War, 1939-1945 2 Amphibious warfare 1 Anti-apartheid activists 1 Apartheid 1 Armed Forces 1 Armed forces 1 Australia 1 Balance of power 1 Combined operations (Military science) 1 Conflict management 1 Economic aspects 1 Equipment and supplies 1 History, Military 1 International relations 1 Irish question 1 Juvenile literature 1 Labor and laboring classes 1 Military art science 1 Military history 1