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Understanding Library of Congress (LC) Call Numbers

Saint Anselm College Library, like many academic libraries in the United States, uses Library of Congress Classification for call numbers. This system uses a combination of letters and numbers to arrange materials by subjects. This guide will provide an introduction to understanding and using Library of Congress call numbers.

 

What is a call number?

  

A call number is like an address; it tells you where the book is located on the shelf.

Call numbers appear

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Note that the same call number can be written from top-to-bottom, or left-to-right.

 

Reading call numbers

Image explaining Library of Congress call numbers

 

Putting Call Numbers in Shelf Order

  

To understand how call numbers are put in order in Library of Congress Classification, again look at each section of the call number.

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What does the call number mean?

  

Remember that Library of Congress Classification arranges materials by subjects.

  • The first sections of the call number represent the subject of the book.
  • The letter-and-decimal section of the call number often represents the author's last name.
  • And, as you recall, the last section of a call number is often the date of publication.

Image explaining Library of Congress call numbers

 

Why is this important to know?

  

Although the most efficient way to locate materials on a particular subject is usually to perform a subject search in the online catalog and then note the call number for each retrieved item, browsing the shelves can also help you locate material appropriate for your topic. Since books are classified by subject, you can often find several helpful books on the same shelf, or nearby. For example, within the subject classification LB 2395, there may be several guides about how to study.

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Since Library of Congress Classification arranges materials by subjects, knowing the letter(s) for your subject area gives you a place to start browsing the shelves. Which letters represent your subject?

View the Library of Congress Classification Outline

 

Text and images on this page were adapted from Honolulu Community College's Understanding Call Numbers.