Library Classification Systems

The Manhattan College Library uses two classification systems -- the Dewey Decimal Classification System for books acquired before 1980 and the Library of Congress Classification System for books acquired since 1980.


1. Dewey Decimal Classification System

The Dewey Decimal Classification System was created in 1876 by Melvil Dewey, while he was the acting librarian at Amherst College in Massachusetts. Up until this time, public libraries were few in number, and patrons were not permitted to go into the stacks to search for books. Academic libraries of this era were essentially like warehouses. Dewey set about to improve the way materials were organized in libraries so that patrons could have ready access to these materials. He worked to persuade libraries to adopt his standardized system of classification. It was his belief that a uniform system of organizing books and information would ensure that a person could go to any public library in the country and find that the books would be arranged in a similar way.

In the United States the Dewey Classification System is used by most public libraries and some small academic libraries.

In the Dewey Classification System, the call numbers of books begin with a number; for example, 973 for U.S. history.

This system uses ten broad categories for organizing the information, which are as follows:

  • 000-099 -- General Works
  • 100-199 -- Philosophy, Psychology, Ethics
  • 200-299 -- Religion and Mythology
  • 300-399 -- Social Sciences
  • 400-499 -- Language
  • 500-599 -- Science
  • 600-699 -- Technology
  • 700-799 -- Arts and Recreation
  • 800-899 -- Literature
  • 900-999 -- History, Geography, Biography, Travel
These are some examples of books with Dewey call numbers:

  • 415 C548
    Aspects of the Theory of Syntax
    By Noam Chomsky

  • 327.73 T86
    Correspondence between President Truman and Pope Pius XII
    By Harry S Truman

  • 883.1 C632
    Familiar Studies in Homer
    By Agnes M. Clerke

2. Library of Congress Classification System

The Library of Congress developed its own system for classifying information in the early 1900s, because the Dewey Decimal Classification System was not flexible enough to meet the needs of its vast collection. The Library of Congress Classification System is now used in the United States by most academic and research libraries and some large public libraries.

Library of Congress call numbers begin with a letter; for instance, L for education.

The Library of Congress System organizes information into twenty-one broad categories, which are as follows:

  • A -- General Works
  • B -- Philosophy, Psychology, Religion
  • C -- History
  • D -- History
  • E -- History
  • F -- History
  • G -- Geography, Anthropology
  • H -- Social Science
  • J -- Political Science
  • K -- Law
  • L -- Education
  • M -- Music
  • N -- Fine Arts
  • P -- Language and Literature
  • Q -- Science
  • R -- Medicine
  • S -- Agriculture
  • T -- Technology
  • U -- Military and Naval Science
  • V -- Military and Naval Science
  • Z -- Bibliography, Library Science

Some examples of books with Library of Congress call numbers are shown below:

  • HC260 .C6H55 2003
    Consumerism in Twentieth-Century Britain: The Search for a Historical Movement
    By Matthew Hilton

  • HV6432.7 .D89 2005
    102 Minutes: The Untold Story of the Fight to Survive Inside the Twin Towers
    By Jim Dwyer and Kevin Flynn

  • QA76.27 .H55 1999
    Dealers of Lightning: Xerox Park and the Dawn of the Computer Age
    By Michael Hilzik


If there is a decimal point in the call number, keep in mind the actual numerical value of the decimal when trying to locate a book on the shelves. For instance, .7 has a higher value than .6034. Therefore, a book with the call number 974.8 is shelved after a book having the call number 974.7969.


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Last modified: August 24, 2007, N. Taylor
For comments or questions, contact: nick.taylor@manhattan.edu