Library Research Tutorial: Adapted from Canvas Course

You may have used Dewey Decimal call numbers in the past. The Dewey Decimal System is used by most public and school libraries to classify and shelve library materials. 

At the UNK Library, and in most other academic libraries, call numbers based on the Library of Congress Classification System are used instead..

A Dewey or Library of Congress (LC) call number serves as an "address" for placing library materials on the shelf, together by subject. You don't need to memorize the table below; just remember that LC call numbers begin with one or more letters based on subject.

Library of Congress Call Number Classes

Reading Library of Congress Classification Numbers

The first line of a Library of Congress call number begins with one or two letters. These letters should be read in alphabetical order. A call number that begins with A is shelved before one that begins with B, and a call number that begins with QE is located some distance before one that starts with QK.

 The second line of a call number consists of one or more numbers. This line is read in numerical order, so that a smaller number precedes a larger number.

The third line is the most difficult part of the call number. The letter following a period is shelved alphabetically, thus:

 However, the number on this third line is read like a decimal. Thus, these examples are in correct call number order:

This makes sense if you read these numbers as decimals!

 The final line of a call number may include a date, volume indicator, issue number, copy number, or other annotation. These are shelved in numerical order following the preceding lines as shown below.