The University of Illinois Library uses several different classification systems to organize materials in various locations across campus. The two most common systems are the Dewey Decimal system, which is used in the Main Stacks, and the Library of Congress system.

This guide provides an overview of different classification systems used in our library system. If you have questions about classification systems, finding and accessing items, or anything else, please use our ask a librarian service to contact us by chat, phone, email, or in person at the Main Library.