LIB 101:  Fundamentals of Library Research

About Library Catalogs

Instructor: Carolyn Oldham Library Office Phone: (562) 908-3417
Email: coldham@riohondo.edu My Phone:  

  This page was last updated on:   Thursday, January 22, 2009

Reading Call Numbers

A call number is the equivalent of an address for finding an item on the shelf. Call numbers also attempt to identify the primary subject of a book so that books on the same subject are shelved together. The letters and numbers chosen for the call numbers are based on the classification system used by that particular library. Most public libraries use the Dewey Decimal Classification system. Call numbers based on the Dewey system start with numbers, such as 351.761 W412. Most college and university libraries use the Library of Congress Classification system. Call numbers based on the Library of Congress system begin with letters and then add numbers, such as HV5132.W43 1989.

The Library of Congress Classification System (LC) divides information into subject sections. Each main section has been given a letter. More letters and numbers are added until each item has a specific call number.

Example:

N               Art
ND                Painting
ND 2608             Mural painting
ND2608.H84 1989    “The Mexican Muralists in the United States” by Laurance P. Hurlburt.

You can see the entire Library of Congress Classification System at:
http://www.carl.org/tlc/crs/LCSO0001.htm


The same call number can be written from top-to-bottom, or left-to-right.
Call numbers appear on the side of books:
LB
2395
.C65
1991

and in the online catalog:
LB2395.C65 1991

When you are looking for the book on the library's shelves, read the call number one line at a time.

The first line is shelved alphabetically, H, HD, HQ, HV, etc.

The second line is shelved by whole number, just like counting

HV

HV

HV

HV

HV

28

95

640

875

2440

The third line begins with a letter that is shelved alphabetically, followed by a number that is read as a decimal instead of a whole number.

HV

HV

HV

HV

HV

875

875

875

875

875

.A3428

.A53

.K32

.K592

.K66

The fourth line is the copyright date of the book. If there are several editions of the same book, they will be shelved in date order: 1997, 1998, 1999, 2000, 2001, etc. Dates have not always been included in call numbers, so most books more than 20 years old will not have a date in the call number.


Search the library catalog or browse the shelf??
Browsing the library's shelves for books on your topic can often be helpful. However, if you want to find all the books the library has on your topic it is important to search the library catalog. Do not assume all the books on the topic will be found together. In theory, assigning call numbers based on a classification system allows the books to be shelved together by subject. However, books do not always fit neatly into the subject sections. For example, where would you find the book titled Science, Philosophy, and Human Behavior in the Soviet Union? It could be put in the Q section for science, in one part of the B section for philosophy, or another part of the B section for human behavior, or in the D section with books about the Soviet Union. Since the book can only be in one place, people who are browsing the shelf in the other subject areas will not be aware of this book. There are also different perspectives on the same subject. For example, the subject of drug abuse includes books on the social aspects that are in the HV section, books dealing with the medical aspects that are in the R section, and books dealing with the legal aspects in the K section. People who are browsing one of these sections will not be aware of the books in the other sections.


2003 Robin Babou