Call Numbers Explained

Call Numbers Explained

Each book in the PUC library is shelved by subject.  Each book has a unique label on the outside that has coded information about the subject and author of the book. This is the call number.

Books are separated into 21 subject categories identified by a letter of the alphabet. A sub-category and author will be identified by a combination of letters and numbers.


  • D is the category for World History
  • DA is a sub-category for Great Britain
  • DA 750-DA 890 is the specific range for books on Scotland
  • DA 775 .B37 2000  is a particular book on medieval Scotland, written by A. Barrell and published in 2000.

Basic Categories

  • A          General Works
  • B          Philosophy, Psychology, Religion
  • C          Auxiliary Sciences of History
  • D          World History & History of Europe, Asia, Africa, Oceania
  • E-F       History of the Americas
  • G          Geography, Anthropology, Recreation
  • H          Social Sciences
  • J           Political Science
  • K           Law
  • L           Education
  • M          Music
  • N          Fine Arts
  • P          Language & Literature
  • Q          Science
  • R          Medicine
  • S          Agriculture
  • T          Technology
  • U          Military Science
  • V          Naval Science
  • Z          Bibliography, Information Science

View a detailed outline of the Library of Congress classification system