History -- 4 History 3 Politics and government -- 3 Economic conditions -- 2 Economic policy -- 2 Foreign economic relations -- 2 Foreign relations -- 2 more ... Relations -- 2 American Border Region -- 1 Antiquities 1 Boundaries -- 1 Case Studies 1 Case studies 1 Civilization 1 Commercial policy 1 Congress 1 Congress -- 1 Culture 1 Directories 1 Economic conditions 1 El Chamizal (Mexico and Tex.) 1 Encyclopedias -- 1 Environmental conditions -- 1 Forecasting 1 Forecasts 1 Foreign trade promotion -- 1 Guidebooks 1 Handbooks, manual, etc. -- 1 Imports -- 1 Industries -- 1 less ...