Skip to main content

Books & eBooks: Library of Congress (LC) Call Numbers

Understanding Library of Congress [LC] Call Numbers

Auraria Library uses the Library of Congress (LC) classification system.

What is the Library of Congress (LC) classification system? LC is an alpha-numeric system that groups books, journals and other materials by subject categories on the library shelves. 

What are call numbers? Call numbers are groups of letters and numbers that classify library items by subject. Items are arranged on bookshelves by call number. Think of it as an address for items in a library. The call number is attached to the spine of the book or a corner of the cover. 

How do I read an LC call number? Read from left to right and top to bottom. The first letter of an LC call number indicates the general class the item falls within. If there is a second letter, this indicates a more specific class. The numbers following define the subject of the book. The Cutter Number is the next set of letters and numbers, and it further distinguishes the book. The Cutter Number indicates the author or title of the book. The edition is the next part of the call number. The year of publication follows the Cutter number to indicate the edition.

Why is this important? It can be very useful to browse bookshelves to find books about a specific or similar topic, you will need a call number to do this. Find a book that looks interesting and locate the book on the bookshelf. Other books next to or near this book on the shelf will be about the same or similar topics.

Call number in a Skyline catalog record

Above is a Skyline catalog record for a book, with the book's call number.  Use the call number to locate the book on the shelf.


Call number on the spine of a book

Above is what the book's call number looks like on the spine of the book.

Reading Library of Congress [LC] Call Numbers

How to Read LC Call Numbers [ in this example ]

  • The first line, alphabetical, identifies the subject area of the book.
  • The second line, a whole number, identifies the subject in more detail.
  • The third line puts items in author's last name order, alphabetically.
  • The last line is the year of publication










Image Credit: Honolulu Community College Library, Nadine Leong-Kurio

Why Is LC Classification Important To Know?

Because books are classified by subject, you can often find similar books nearby. However, larger subject areas may be divided between two or more classifications because the cataloging identifies other aspects of the general subject. For example, books on various "Cultures," may be found in several subject areas, that is, DT, E, F, GN, HD or PQ.