North Hall Library


LC Classification

A step by step guide to mastering the Circulation Desk

Library of Congress Classification

There are two popular classification systems in use in the United States: the older Dewey Decimal System (found primarily in school and public libraries) and the more recent Library of Congress Classification System (used in most academic libraries). 

At North Hall Library we use the alphanumeric Library of Congress Classification System. This allows us to easily and efficiently keep track of large amounts of books. As a library student assistant, part of your responsibility will be to use this system to shelve and/or locate books, while ensuring the shelves are properly ordered. This tutorial will teach you how to use the LC system to shelve books, shelf-read, and to perform general stack maintenance.

Call number 'LB 2395 .C63 1991' on the spine of a book and in the online catalog

Note that the same call number can be written from top-to-bottom or left-to-right, depending on what format you are reading. While our online catalog displays call numbers from left-to-right, the majority of our materials features a vertical (top-to-bottom) call number label.

The LC system allows books to be arranged by subject into 21 subject classes.  Each book is assigned an alphanumeric call number based on its subject matter. For a full list of classifications, see here (note that you will not be required to know subject classifications).

Structure of a LC Call Number

Here is an example of the structure of a LC call number:

Book title: Uncensored War: The Media and Vietnam                                                Call number 'LB 2395 .C65 1991' on the spine of a book and in the online catalog
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.

Tutorial Videos

Watch the following tutorial videos for a better understanding of reading and finding LC Call Numbers.



How to Read a Call Number

Read call numbers line by line:

Read the first line in alphabetical order:                                                                                      Call number 'LB 2395 .C65 1991' on the spine of a book and in the online catalog
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...

Volume Numbers

Sometimes a call number will contain a volume number, labeled v.1, v.2, etc. These are shelved in whole number numerical order within the set of books.

Copy Numbers

A call number will contain a copy number if there are multiple copies of the same book on the shelf, labeled c.1, c.2, etc. These are shelved in whole number order.

One thing to always keep in mind when shelving books and shelf-reading is that nothing comes before something.

If a book contains no volume number, that book comes before a book within a set that does contain a volume number. If a book contains no date in the call number, that book comes before the same book that does have a date in the call number.

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

Ten Library of Congress call numbers in order on a shelf. On the first line, 'LA' before 'LB'.  On the second line, '2327' before '2328'. On the combination letter number line 'B' before 'C'. For the numbers after the letter on the combination line, '.55' before '.554' and '.554' before '.63'.  For the last line, '1987' before '1991'.

Understand ?

Once you feel that you have a clear and precise understanding of Library of Congress call numbers, it is time to put that to the test. At the Circulation Desk sit at the third workstation (the one closest to the door). Double click the LC Easy icon on the desktop to open the tutorial. Fill out your name and what area you are working in (Circulation). You will then read through the lesson, teaching you about LC classification. This is just to reiterate what you learned. Then, complete both of the drills (shelf reading and book sorting). When a certificate pops up with a score, print it out and return it to your supervisor when finished. All student assistants must receive a passing score to move forward.

It is important to remember that you are not being timed -- so move at a pace that is most comfortable for you to understand what you are learning and be certain of the answers you are giving. Accuracy over speed will always be the best policy at North Hall. If you are not happy with your score at the end, feel free to take it again. This is an exercise for you, to ensure that you will comfortable in your position.