It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Listed below are the letters and titles of the main classes of the Library of Congress Classification. Click on any class to view an outline of its subclasses in an interactive PDF format. This list is based on the Library of Congress Classification Outline.