History 22 Tank warfare 9 World War, 1939-1945 8 Economic conditions 7 Campaigns 6 Firearms 6 Military art and science 6 Banks and banking 5 Case studies 5 Remote sensing 5 Technological innovations 5 Military research 4 Politics and government 4 Tanks (Military science) 4 Armoured vehicles, Military 3 Biography 3 Economic policy 3 Equipment 3 Handbooks, manuals, etc 3 Infantry 3 International relations 3 Leadership 3 Military policy 3 Periodicals 3 Pictorial works 3 Vehicles, Military 3 Acquisitions (Libraries) 2 Aerial operations 2 Airborne troops 2 Asia 2