Library of Congress Classification System

How to Read Call Numbers

Classification systems are used organize the books on the shelves. A classification system uses letters and numbers to make sure books on the same topic are placed together. This arrangement lets you find the book you're looking for and other books like it on the same shelf.

Academic libraries (such as the UWEST library) use Library of Congress Classification System (LC). K-12 and public libraries use the Dewey Decimal system to classify their books.

Anatomy of a Library of Congress Call Number

Book title: Uncensored War: The Media and Vietnam
Author: Daniel C. Hallin
Call Number: DS559.46 .H35 1986

The first two lines describe the subject of the book.
DS559.45 = Vietnamese Conflict

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

The last line represents the date of publication.

Tips for Finding Books on the Shelf

Read call numbers line by line.

LB
Read the first line in alphabetical order:
A, B, BF, C, D... L, LA, LB, LC, M, ML...

2395
Read the second line as a whole number:
1, 2, 3, 45, 100, 101, 1000, 2000, 2430...

.C65
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

Some call numbers have more than one combination letter-number line.

1991
The last line is the year the book was published. Read in chronological order:
1985, 1991, 1992...

Here is a shelf of books with the call number order explained.

What Do the Call Numbers Mean?