Understanding Call Numbers

Introduction, Instructions

This tutorial is intended to give you a broad overview of different Call Numbering systems and how they work. You will learn how items are classified within each system, what the call numbers mean and how to find an item based on its call number.

This tutorial should take approximately 20 minutes to complete.

Call Numbers - An Introduction

Materials in libraries have to be organized in some way so that things can be found once they have been placed on a shelf.

Each item is assigned a unique code, called a call number, to help with organization.

• Call numbers are usually made up of numbers and letters and sometimes include punctuation marks like colons or dots
• Call numbers determine each item's exact location within a library
• Call numbers are assigned to items so that they bring together materials which are alike in some way, usually by subject

Classification Systems are the rules used to determine call numbers.

Most libraries, like public and academic libraries use standardized classification systems, but some (mostly special libraries) come up with their own classification system unique to their own needs and collections.

This tutorial will give a brief breakdown and explanation of several call number systems with tips on how to read the various numbers properly. A basic understanding of call numbers is necessary in order to find materials, and ultimately the information you need, in the library.

The most frequently use classification systems are :

• Dewey Decimal Classification System (Dewey) - Used by most public and school libraries.
  Dewey call numbers begin with a three digit number.
  In the online catalog, typical Dewey call numbers look like:
  • 813 AL355L 1987
  
  On book spines, or labels on other materials, Dewey call numbers are arranged vertically and would typically look like:
  • 813
    AL355L
    1987

• Library of Congress Classification System (LC) - Used by most academic libraries and in other larger libraries.
  LC call numbers begin with letters.
  In the online catalog, typical LC call numbers look like:
  • PS 1017 .L5 1983
  
  On book spines, or labels on other materials, LC call numbers are arranged vertically and would typically look like:
  • PS
    1017
    .L5
    1983

• Superintendent of Documents (SuDocs) - Used by libraries with extensive collections of materials published by the United States Government
  SuDocs call numbers begin with letters and always include a colon.
  SuDocs call numbers typically look like:
  • HE 20.3002:R 24/5

Libraries may use one or all of these systems, based on the collections they own.

LSU Libraries use all of the above systems, as well as some other classification systems which are specially suited to certain special collections.