Atkinson Library

Understanding LC Call Numbers

Each item in the library’s collection has a unique call number, which tells where the item is located on the shelves. Jackson Community College Library uses the Library of Congress (LC) Classification, which arranges items by broad/general subjects, and then by sub-subjects so subject-related items are shelved together and more easily located.

Library materials are shelved alphabetically and numerically depending on the call number, which is determined by the item's subject. Also, call numbers have been assigned to many well-known authors so their works are shelved together.

Once you locate an item's call number and collection area (reference, oversize, children’s, etc.) in the library's catalog, you can find the item, as well as browse for additional items with similar call numbers. Knowing the letter(s) for your subject area also gives you a place to start when browsing the shelves.

For an overview of the Library of Congress classification system, see the Library of Congress Classification outline, which shows the letters and titles of main classification classes and is offered online by the Library of Congress Cataloging Policy and Support Office.

Call numbers appear in two formats and are read from top to bottom or left to right, as shown below:

Stacked on the
spines of books
Z
678.9
.H9
1987
In a single line in the library's catalog
Z678.9.H9 1987

When reading call numbers, consider each segment before moving on to the next segment. This process is further explained below.

The following table offers explanations and examples of the segments of Library of Congress call numbers. In each row, call numbers are arranged in correct shelf order to show how they would be arranged on library shelves. Bold type indicates the portion of the call number being discussed.

Letter(s) make up the first segment and indicate an item's subject and sub-subject. H
41		 HA
17		 HB
34		 HC
240
The library's arrangement is based on these letters, and is alphabetic. .E561 .K4
1971		 .N6
1990		 .C518
2000
Numbers comprise the next segment and define the subject matter more specifically.

Read these numbers as whole numbers. If this component contains a period and another number (i.e. 678.9 and 678.93), read it like you would a whole number with a decimal.

 Z
665
.M672
1984		 Z
674
.K35		 Z
678.9
.H9
1987		 Z
678.93
.M53
A54
1987
Letters and numbers comprise the next segment and indicate an author's last name or a subject subdivision.

Read the letters alphabetically.

Read the numbers after the letter as decimals.

 KF
387
.C53
M3.1
.M466		 KF
387
.H36
M3.1
.M5		 KF
387
.K55
M3.1
.M84		 KF
387
.L37
M3.1
.M9
Another segment of letters and numbers may follow the previous one.
Again, read the letters alphabetically and the numbers as decimals.
The late segment, if given, indicates the item's publication date.

Items with the same call number are shelved chronologically by publication date.

 PS
3515
.U274
A19
1968		 PS
3515
.U274
A6
1969		 PS
3515
.U274
A6
1971		 PS
3515
.U274
A6
2000

Thanks to Tarleton State University for this information:

Research Databases | Library Catalog | Web Resources | Library Information | Library Home

Atkinson Library, JCC, 2111 Emmons Road - Jackson, Michigan 49201-8399 - Phone: (517)796-8622