A    General Works

   B    Philosophy. Psychology. Religion

   C    Auxiliary Sciences of History

   D    World History and History of Europe, Asia, Africa, Australia, New Zealand, etc.

   E    History of the Americas

   F    History of the Americas

   G    Geography. Anthropology. Recreation

   H    Social Sciences

   J    Political Science Law

   K    Law

   L    Education

   M    Music and Books on Music

   N    Fine Arts

   P    Language and Literature

   Q    Science

   R    Medicine

   S    Agriculture

   T    Technology

   U    Military Science

   V    Naval Science

   Z   Bibliography. Library Science. Information Resources(General)