WKU Library Guide: How to Read Call Number

August 16, 2025 | Library News | WKU library

Through the previous library guide, you have already learned how to find your desired books through the Discover system. Now, once you have the book's call number, how can you locate it in the vast sea of books? This guide will help you solve this problem with ease!

Introduction to Call Number

The call number is the code used by the library for organizing, locating, borrowing, returning, and cataloging books. It serves as the primary basis for lending documents and inventory checks, indicating the location of the collection. Wenzhou-Kean University Library uses the Library of Congress Classification system, a comprehensive hierarchical classification developed by the Library of Congress, which is divided into 20 main categories. Each physical book has its corresponding call number attached.
Wenzhou-Kean University’s call number consists of three parts. The first part, made up of letters, numbers, and dots, represents the main category and subcategories of the book’s subject (as shown in rows 1-3 of the figure below); The second part, consisting of letters and numbers, indicates the author or title of the book (as shown in row 4 of the figure below); The third part, made up of letters and numbers, represents the publication year of the book, volume number, copy, and language (as shown in rows 5 of the figure below).

How to Find Books Using Call Number

First, based on the search results in the system and the collection distribution Guide, determine the specific floor and location of the book.

Next, upon reaching the designated area, use the call number range on the side labels of the shelves to determine the approximate location of the book.

Finally, use the book's unique call number to locate it on the corresponding shelf.

Next, it’s time for the specific step of reading the call number and finding the book!
In general, the library books are arranged from left to right, top to bottom, forming a roughly 'Z' shape. This is shown in the figure below:

Step 1:

Check the call number on the spine of the book (the side of the book). The call number is usually located in the lower middle of the spine of the book.

Step 2:

Start by comparing the alphabetical ordering of letters on the top lines of the book call numbers. Therefore, books beginning with A in the first line must be placed before books beginning with B. Secondly, the individual letters of the first line are arranged before the compound letters. Compound letters are then compared in order, i.e., when the first letter is the same, the second letter is compared in order of the 26 letters.
For example, in the chart above, G comes before L in alphabetical order; thus, G89 E93 2006 comes before L65 L33 S78 2021. Then, L is a single letter and LA is a compound letter, so L65 L33 S78 2021 comes before LA11 M13 2011.

Step 3:

If the letters are the same for the first lines of call numbers, then compare the ordering of the numerical sequences on the second lines. For example, let’s compare DR583 Y68 2017 to DR592 K4 D56 2020 in the picture above. When the first line of both call numbers is DR, it is necessary to compare the second line, and 583 is smaller than 592. Thus, the book with the call number DR583 Y68 2017 is placed before the book with the call number DR592 K4 D56 2020.

Step 4:

When the first two rows are the same, the third row still follows the principle of letters plus numbers, but note that the numbers here are decimals and should be compared according to the principle of comparing decimals (view letters as decimal points).
As shown in the picture above, in the book with call number GA102.3 R36 2016, ".3" means 0.3. If a book with call number GA102.295 R36 2016 appears at this time, because 0.295<0.3, it should be placed to the left of the book with call number GA102.3 R36 2016;

Step 5:

If the first few rows are the same, continue to compare the remaining rows according to the method mentioned above. For example, if the first few lines of the call number GA102.295 R36 2016 and the call number GA102.295 R36 2020 are the same, the last line is compared, and 2016 is smaller than 2020, so the book with the call number GA102.295 R36 2016 is arranged in front of the book with the call number GA102.295 R36 2020.

Now it's time to test your "book-searching" skills! Please carefully review the following book call numbers and see if you understand their meaning and why the books are arranged in this order. Try to spot any mistakes in the process!