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How to Read a Call Number: Reading Call Numbers

How to Read a Call Number

What is a call number? 

A call number is a unique number given to an item that identifies the location and subject content of materials in a library.  Call numbers are found on the spine of the book or the upper left hand corner of an item. 

Library of Congress (LC) Call Numbers 

The Library of Congress Classification System uses a combination of letters and numbers to arrange materials by subject. 

The example below identifies each element in a LC call number:
LB       LC Classification number (subject content)
2395   
.A66    Author and book number
1990   Publication Date

LB  -- The first line of a call number represents one of 21 subject divisions of the LC System.  This number helps define the subject matter of the item.  These 21 categories are furthered divided by adding one or two additional letters and a set of numbers. 

L = Education
LA = History of Education
LB = Theory and Practice of Education

When reading a call number, the first line is read in alphabetical order.

L comes before LA, before LB, before LC, etc.  N before NB before RJ before SA

2395 -- Numbers immediately following the first letters are treated as whole numbers: LB 5 before LB 90 before LB 888

.A66 -- The third line is a combination of letters and numbers. The letters are read in alphabetical order, with the number after the letter treated as a decimal: .A66 before .A7 before .A9000

Reading call numbers on the shelf -- In order to locate a particular item from the shelf, please read all the lines of the call number. 

Because there are many locations in the library, first determine where in the library the item is located.  Note the Location in the EWU Library Catalog record -- this will tell you on what floor the item is located.

After you determine the location of the item, the call number is read line by line.  It is very important that you write down the entire call number to retrieve the desired item. Look at the following call numbers. They are in correct call number order.

PR
2456
.D86
1997
PS
67
.J654
2001
PS
327
.E48
1985
PS
2458
.F42
2004
PS
2458
.F6
1987
PS
2458
.F922
1999

 

Browsing the shelf

Once you understand how to read a call number, you can browse the collection to find similar books on a topic arranged with the same call number.  For example, books that discuss recreation and leisure will have the call number GV.  Likewise, if you browse the periodical collection with this call number, you will find print magazines and journals on recreation. 

Superintendent of Documents (SuDoc) Call Numbers 

The SuDoc Classification System is used by the U.S. Government Printing Office to assign call numbers to government publications. SuDoc Call numbers are alphanumeric based on the agency that produces the item rather than the subject content as with LC.  They are usually written on one line on the upper left hand corner of the item, but can also be found on the spine.  Usually SuDoc call numbers have colons in their call numbers, which distinguishes them from LC call numbers.

For example:  C3.2:Ag 8/8/992

The example below identifies each element in a SuDoc call number:

C    Agency that produced document (Commerce Department)
3    Subagency (Bureau of the Census)   
.2   Series (General Publications)
Ag 8/8/992  Title and date (Agricultural Census, 1992)

Written by Rachel Fenske 5/2000

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