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Understanding Call Numbers
Overview
Call numbers are like street addresses for books and other library items. They tell you where to find an item on the shelf and what subject it relates to. At Capitol Technology University, the Puente Library uses the Library of Congress Classification (LCC) system, which organizes materials by broad subject areas using a combination of letters and numbers.
In this article, you’ll learn how to read and understand a call number, how call numbers are ordered on the shelf, and how to use them to locate books and explore related materials.
What is a Call Number?
A call number is a unique identifier assigned to each library item. It helps:
- Organize materials by subject.
- Identify the author or title.
- Indicate the year of publication.
- Determine where the item is located in the library.
You’ll see call numbers:
- Printed on a book’s spine (vertically).
- Listed in the online catalog (horizontally).
Example Call Number: QA76.9.A25 S268 2014
Components of a Call Number (LCC Format)
Each part of a call number provides specific information:
Component | What It Means |
Letters (1st line) | Broad subject category and subcategory. |
Whole Number (2nd line) | Further narrows the topic within the subject. More specific topic within the subject. |
Decimal with Letter (3rd line) | Known as a Cutter Number. Represents the author (or sometimes the title). |
Year (4th line) | Year of publication. |
Some call numbers also include:
- A second Cutter number (often related to the subject).
- A volume number (e.g., v.1, v.2).
- A copy number (e.g., c.2, c.3).
How to Read a Call Number (Line by Line)
Call numbers are read line by line, and each part is sorted in a specific order:
Line | How to Read It |
Line 1: Letters | Alphabetically (A, B, BF, C, D, E… LB, LC). Single letters come before double letters. |
Line 2: Numbers | As whole numbers. Example: 32 comes before 310. |
Line 3: Cutter Number | For call numbers with two Cutters, they are both read Alphabetically by the letter, then decimally by the number. Example: .C65 comes before .C7. Not all call numbers will have a 2nd Cutter, or the fourth line. |
Line 4: Year | Chronologically. Example: 1987 comes before 1991. |
Tip: If the Cutter number appears confusing, imagine the shorter number with an added zero for easier comparison. For example: .B7 can be thought of as .B70, which helps you see that .B64 comes first.
Why It Matters
Call numbers allow:
- Easy location of library items.
- Browsing of related materials nearby.
- Efficient shelving and reshelving by library staff.
- Precise cataloging of items based on subject, author, and edition.
Troubleshooting
Issue | Solution |
I found the book in the catalog but can’t find it on the shelf. | Double-check the call number and the location prefix (e.g.,Stacks, Reference, Circulation Desk). Each section of the library may shelve items differently. |
The call number doesn’t match what’s on the book. | It might be a different edition or copy. Use the catalog to verify title, author, and publication year. If you think you’ve found an error, Ask a Librarian. |
The book has multiple Cutter numbers or volume indicators. | Review each line carefully. Books with similar subjects will appear together, but may differ by author, title, edition, or volume. |
Still Need Help?
If you’re having trouble locating a book or understanding how to read call numbers, reach out to Ask a Librarian or visit the circulation desk for assistance.