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Library of Congress Classification System: How to Read Call Numbers

Call Numbers

How Do I Read Library of Congress Call Numbers?

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

The classification system is designed to group library materials of similar subjects together and is used by many universities and colleges.

Here is a sample of items in call number order:

Tips for Finding Books on the Shelf

Call number 'LB 2395 .C65 1991' on the spine of a book and in the online catalogRead 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

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

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.

*Information from the University System of Georgia

Click here for a detailed list of Library of Congress classifications. (opens in new window)