History|History of North and South America|History: America|United States|United States History 147 History|History of North and South America|History of the Americas|History: America|United States 96 Military and Defense|Military and Naval Science|Military History & Science|Military science|Military science (General) 37 Civil War period, 1861-1865|History|History of North and South America|History of the Americas|History: America|United States 29 American Civil War|Civil War period, 1861-1865|History|History of North and South America|History: America|United States 24 History|History of North and South America|History: America|Presidential Studies|United States|United States History 22 Archaeology|Auxiliary Sciences of History|Geography and Anthropology 21 America|History|History of North and South America|History: America|Indians of North America|United States History 20 Asian History|History|History (General) and History of Europe|History of Asia 20 Colonial history (1607-1775)|History|History of North and South America|History of the Americas|History: America|United States 20 Colonial history (1607-1775)|History|History of North and South America|History: America|United States|United States History 20 History 18 History|History (General) and History of Europe 15 Abstracting, Bibliographies and Statistics|Education|Higher Education|History of education|Theory and practice of education|United States 14 Education|Higher education|History of education|Theory and practice of education|United States 12 European History|History|History (General) and History of Europe|History of Europe 11 America|History|History of North and South America|History of the Americas|History: America|Indians of North America 10 Education|Higher education|History of education 10 History|History of North and South America|History: America|Twentieth century|United States|World War I 10 History|History of North and South America|History: America|United States|World War I 10 Business and Economics|Business and Economics (General)|Economic History|Economic history and conditions|Economic History, Conditions|Social Sciences 9 European History|History|History (General) and History of Europe|History of Europe|History of Great Britain 9 Fine Arts and Music|History and criticism|Literature on music|Music|Music and books on music 9 Academic Testing|Education|History of education|School administration and organization|Tests and Measurements|Theory and practice of education|United States 8 Academic Testing|Education|History of education|Tests and Measurements|Theory and practice of education|United States 8 African History|History|History (General) and History of Europe|History of Africa 8 Armies: Organization, distribution, military situation|Military and Defense|Military and Naval Science|Military History & Science|Military science 8 Asian History|China|History|History (General) and History of Europe|History of Asia 8 Civil War period, 1861-1865|History|History of North and South America|History: America|United States|United States History 8 History|History of North and South America|History of the Americas|History: America|The Revolution, 1775-1783|United States 8