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Writing 10 (Ayik) - Spring 2024

About Call Numbers

A call number is a combination of letters and numbers which identifies the location and subject matter of books and other library resources.

Think of a call number as an address for a book on the library shelf. Be aware that books on similar subjects will appear next to each other.

Locate call numbers on the spine of a book or at the upper left-hand corner.

Call Nos Locations on Books

Most academic libraries use the Library of Congress Classification (LCC) system to generate call numbers.

Reading a Call Number

To read a call number, look at each part separately. Read from left to right and top to bottom. Let's look at the number E645 .H37 2021 for the book titled: Monumental Harm: Reckoning with Jim Crow Era Confederate Monuments by Hartley.




Line 1

Books are arranged in alphabetical order from the first letter(s) on the first line of the call number.

E would come before EA; ES would come after EA and before EZ.

Call Number Graphic

Line 2

After the letter(s), books are ordered numerically. Numbers are treated as whole numbers. 645 is read as a whole number. For example, 645 numerically comes after 641 and before 675.

Call Numbers 2nd Line

Line 3

This starts with a letter organized in alphabetical order, followed by a number read as a decimal, NOT as a whole number.

So .H37 will come after H211 (since .211 becomes before .37) and before H4 (since .37 comes before .4).

Call Numbers 3rd Line

There may be additional lines read in the same way.

Last Line

The last line will be the date of publication.

Call Numbers 4th Line - Publication Date

What Call Numbers Mean

  • The Library of Congress Classification (LCC) system has 21 classes, each identified by a letter of the alphabet. Sub-classes are identified by a combination of two or three letters. Topics within sub-classes ( or time period) are broken down into one or more numbers.

Here is an example:


QP is the class and subclass. The class is the subject of the book. Class Q is for Science and Subclass QP is for Physiology.

458 is the classification number which indicates a narrower subject of Neurophysiology and Neuropsychology.

K54 is the Cutter number which can represent the author, title, a more precise subject etc. Note: Some call numbers have more than one Cutter number.

2017 is the year of publication. Older books may not include it.


Understanding Call Numbers (2:11) is an excellent summary of call numbers and how to read them.

from Pollack Learning eLearning @Cal State Fullerton

Finding Print Books at the UC Merced Library

from our 2021 Library Tour