Call Numbers

What are Call Numbers

Most items in the collection are arranged by subject. Each item is assigned a unique call number that indicates not only where the item is located but provides other valuable information about the item as well. Items about the same subject have similar call numbers. Therefore, they are grouped together on the shelf. This makes it easier for users to browse items on a particular topic.

Location Prefix

Some call numbers are preceded by a location prefix. A location prefix means that the item belongs to a specific collection, is shelved in a special place, and may have circulation restrictions. For example, in the call number, Ref AG243 .G87 1992 , the Ref prefix indicates that the item is shelved in the Reference Collection. Items in the Reference Collection do not circulate.

Library of Congress (LC) Call Numbers

LC call numbers always begin with a letter of the alphabet that identifies the main class or subject of the item. LC main classes and their corresponding letters in the alphabet are listed below:

  • A: General Works
  • B: Philosophy, Psychology, & Religion
  • C: Auxiliary Sciences of History
  • D: History - General & Old World
  • E: History - American & North American
  • F: History - U.S. & South American
  • G: Geography, Anthropology, & Recreation
  • H: Social Sciences
  • J: Political Science
  • K: Law
  • L: Education
  • M: Music
  • N: Fine Arts
  • P: Language & Literature
  • Q: Sciences
  • R: Medicine
  • S: Agriculture
  • T: Technology
  • U: Military Science
  • V: Naval Science
  • Z: History of Books, Library Science, & Bibliography

See the Library of Congress for a complete list of main classes and their subclasses.

How to Read LC Call Numbers

Subclasses of the LC main classes are represented by a second letter. The first D in the call number indicates that the book is a work of history. The second D indicates that it is a work of German history.

DD
534
.C35
1998

LC call numbers are read line-by-line as explained in the following table.

Line Number
Part
How to Read
Represents
1
First letter

In alphabetical order
A, B, C, D, etc.

Main class
Second letter

In alphabetical order
BA, BB, BC,BD, etc.

Subclass
2
Number

As a whole number.
1, 2, 3, 45, 534, 2000, 2500, etc.

Further subclasses
3

Letter

In alphabetical order
.C, .D, .E, etc.

Author's last name
Decimal

Number-by-number
.C22, .C34, .C35, .C357, etc.

 
4
Date

In chronological order
1995, 1998, 2000, etc.

Date published
Volume

In numerical order
1, 2, 3, 4, etc.

Volume published

LC Call Number Shelf Order  

LA before
LB
2327 before 2328
. B before
.C5
. 554 before
.63
1987 before
1991
LA
2301
. M37
LB
2327
. M3
LB
2327
. P35
LB
2328
. B3
LB
2328
. B34
LB
2328
. C55
LB
2328
. C554
1982
LB
2328
. C63
1992
LB
2395
. C65
1987
LB
2395
. C65
1991
    
. M before
.P
. 3 before
.34
. 55 before
.554
2328 before
2395