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English Literature & Literary Criticism: How to Read a Call Number

Library of Congress Call Number Headings

Find out the main classes and subclasses of the Library of Congress Classification taxonomy

How to Read a Call Number

How to read call numbers in an academic library

Libraries use classification systems to organize the books on the shelves. A classification system uses letters and/or numbers (call numbers) to arrange the books so that books on the same topic are together. This arrangement results in "serendipitous browsing". You find one book in the catalog, go to the shelf, and, then find an even better book is sitting right next to it.

From the Online Catalog to the Shelf

Libraries in the United States generally use either the Library of Congress Classification System (LC) or the Dewey Decimal Classification System to organize their books. Most academic libraries use LC, and most public libraries and K-12 school libraries use Dewey.

At WMU Libraries, we use both.  The majority of books are arranged by LC.  However, we do have a collection of children's and young adult books that are arranged by Dewey.

The Library of Congress Classification System (LC)

(Even though it starts with letters , it is called a number. )


Book title: The war behind me : Vietnam veterans confront the truth about U.S. war crimes
Author: Deborah Nelson
Call Number: DS559.2.N45 2008

 *The call number will appear on one line in the catalog, but it will appear on several lines on the spine of the book. 

Start by separating the Letters: 

DS (which indicates the main classification and subclassification D = history, and DS = History of Asia ). 

The second line describes in more detail the subject of the book.

559.2 = Vietnam War

The third line often represents the author's last name.

N = Nelson

The last line represents the date of publication.


Finally, the call number will look like this on the spine of the book:





Tips for Finding Books on the Shelf

Read call numbers line by line.


Read the first line in alphabetical order:

A, B, BF, C, D... L, LA, LB, LC, M, ML...


Read the second line as a whole number:

1, 2, 3, 45, 100, 101, 1000, 2000, 2430...


The third line is a combination of a letter and numbers. Read the letter alphabetically.

Read the number as a decimal, eg:
.C65 = .65  

.C724 = .724


The last line is the year the book was published.

Read in chronological order:
1985, 1991, 1992...

The Dewey Decimal System

In the Dewey Decimal system, the call number is made up of three parts:  306.89 Pow 199

Book: Family breakup 

Author: Jillian Powell

Call number: 306.89 Pow 1999

1. The call number will look like this on the book:




2. Read the call number line by line.

Dewey number:  306.89

300's are for books about social science topics. 306.89 is on the subject of divorce.

Cutter number:  Pow

The cutter number for a book usually consists of the first few letters of the author's last name.

Date of publication: 1999

The last number is the date the work was published.

The decimal system treats numbers as decimals rather than whole numbers (.12 comes before .2).

"Nothing" always comes before something (.1 comes before .11). Imagine there is a zero after the final number.

Where is it located?

Though not a complete list, this should help you get started with some of our collections.

  • If you see (Ref) at the end of a Call Number, that means it is in the  Central Reference Collection and cannot be checked out.
  • Most items that begin with the letter are found in the Music Library.  
  • If you see a Call Number with a :, it is most likely a government document and found on the second floor of Waldo Library. See here for more information on Government Document Call Numbers (Sudocs). 
  • If there are no letters at the beginning of the call number,  it is more than likely to be  Dewey Decimal Call Number and therefore a children's book.  Children's books are either in Waldo Library (Second Floor) or in the Education Library. 
  • V at the beginning of the call number means it is more than likely in the Instructional Video Collection on the first floor of Waldo Library.
  • Maps of the library with main Library Call numbers can be found near the elevators
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