Call Numbers Demystified!

Library Stacks
What do those letters and numbers mean?

Ever wonder how to read and use those letters and numbers you see on the spine of the books in the library? Need to find the awesome book you found in the catalog but don't know where it is on the shelf? Help is on the way!

The call number of a book (that actually starts with one or two letters in the Library of Congress Classification system) is like the book’s address: it tells you the exact location where it lives on a shelf in the library—but also what it is about. The books in the McHenry and the Science & Engineering Library are shelved by subject, so when you find the right spot on the shelf where your book lives, take a quick look at the books around it—they may be useful to you as well because they are in the same subject area. Browsing is a great way to pick up more than one source at a time and explore the collection with serendipity as your guide.

So how do they work?

Here's a guide that explains how to read them, and what to do if you can’t find your book on the shelf.
And here is a guide that includes an online tutorial on how to use the library’s catalog Cruzcat, where library materials can be discovered.

Roving students who wear yellow vests and walk throughout the library to answer your questions are happy to help you get to the right place to find your book. Make sure to ask them for help—they are here for you!


Brought to you by the Library’s Undergraduate Experience Team.