This page provides an introduction to understanding and using library call numbers. For additional information, contact a reference librarian.
Reading Call Numbers
Every item in the UNM University Libraries has a unique call number. A call number is like an address. It identifies where the book is located in the library. The UNM University Libraries, like most academic libraries in the United States, uses mostly Library of Congress Classification for call numbers. In addition to LC call numbers, there are small collections of older materials still shelved by the old Dewey Classification system and a substantial collection of Government Documents using the Superintendent of Documents (SuDoc) classification system.
LC Classification
This system uses a combination of letters and numbers to arrange materials by subjects. In the LIBROS Online Catalog, call numbers are read left to right like this:
LB2395 .C65 1991
On the item itself, the call number is read top to bottom like this:
LB - The first line is read in alphabetical order (A, B, BF, C, D ... L, LA, LB, LC, M, ML ... ).
2395 - The second line is read as a whole number (1, 2, 3, ...45, ...100, 101, ... 1000, ... 2000, ...2430, 2431, 2432).
C65 - The third line is a combination of a letter and numbers. Read the letter alphabetically. Read the number as a decimal (C65 = .65).
1991 - This is the year the book was published.
Call Number Order
Call number order can be confusing at first. These call numbers are in the correct order:
LA2301 .M37
LB2327 .M3 - LB comes after LA
LB2327 .V53 1990 - Both start with LB2327, V comes after M
LB2328 .B37 - 2328 comes after 2327
LB2328 .C34 - C comes after B
LB2328 .C55 - Both start with LB2328 .C, decimal .55 comes after .34
LB2328 .C554 1982 - Decimal .554 comes after .55
LB2395 .C65 1987
LB2395 .C65 1991 - Same call numbers except for date: 1991 comes after 1987
Library of Congress Classification
Library of Congress Classification arranges materials by subjects. The first sections of the call number represent the subject of the book. The letter-and-decimal section of the call number often represents the author's last name. The last section of a call number is often the date of publication.
example:
Title: What You Need to Know About Developing Study Skills, Taking Notes & Tests, Using Dictionaries & Libraries
Author: Marcia J. Coman.
Call number:
LB2395 .C65 1991
LB2395 - subject of the book: Methods of Study in Higher Education
C65 - Coman, the author's last name
1991 - the year book was published
Because books are classified by subject, you can often find several helpful books on the same shelf, or nearby. For example, within the same call number LB2395, there are other guides for college study.
LB2395 .C6 1960 - A Student's Guide to Efficient Study, by Luella Cole
LB2395 .C65 1991 - What You Need ... Study Skills, by Marcia J. Coman
LB2395 .L447 - Keys to College Success, by Minnette Lenier
LB2395 .O54 1983 - A Successful Student's Handbook, by Rita Phipps