ACO categories follow the Library of Congress Classification system

• All (17,699 )
• Philosophy. Psychology. Religion (4,986 books)
• Language and Literature (3,725 books)
• World History and History of Europe, Asia, Africa, Australia, New Zealand, etc. (2,342 books)
• Law (1,122 books)
• Social Sciences (568 books)
• Education (262 books)
• Bibliography. Library Science. Information Resources (General) (220 books)
• Political Science (185 books)
• Science (156 books)
• General Works (115 books)
• Geography. Anthropology. Recreation (109 books)
• Auxiliary Sciences of History (90 books)
• Medicine (73 books)
• Fine Arts (53 books)
• Agriculture (50 books)
• Technology (38 books)
• Music and Books on Music (37 books)
• History of the Americas (19 books)
• Military Science (12 books)
• Naval Science (3 books)