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Research Guides

Information Literacy & Library Research: Library Classification Systems

Information literacy is the ability to know when information is needed and to be able to identify, locate and evaluate, and then legally and responsibly use and share that information.

Library Classification Systems

Libraries house thousands of print materials, not to mention all the information that is accessible online, such as books, magazines, movies, etc. Because there are so many, it would be impossible to find anything if they weren't organized at all. To make everything easy to find and browse too, several different classification systems have been developed that are used all over the world. The SUU Sherratt Library uses both Library of Congress and the Dewey Decimal systems- Library of Congress Classification is used for the main collection and everything else except the Juvenile and Curriculum collections on the 3rd floor, which are better suited to Dewey.

Note for INFO 1010:

Knowing how to find books and materials in the library is important, especially as you start collecting books to use in your ENGL 2010 papers. In the Module 4 assignment, you will be asked to find a book as well as popular and scholarly articles. If you choose to use the book for the in class portion of the assignment (for those of you in the face to face sections co-rec'd with ENGL 2010), you will need to physically bring the book in as well- which is another reason to know how Library of Congress Classification works.

Library of Congress and Dewey Classification Systems

Section Three A: Find Books and Articles - Finding Books and Media - Library of Congress and Dewey Decimal Classification Systems

‚ÄčLibrary of Congress Classification System

The Library of Congress Classification System is used in most college and university libraries. In the Sherratt Library, the LC system is used in all collections except the Curriculum and the Juvenile Collections on the Third floor, which use the Dewey Decimal Classification System. The DDC is used in school, public, and small libraries.

In 1899, the United States Library of Congress created a classification scheme for books. It is called the Library of Congress Classification system (LC for short). In this system, all knowledge is divided into 21 broad subject areas by letters of the alphabet (I, O, W, X, and Y are not used). There is no significance for the letters of the alphabet chosen for each broad subject area. There is no need to memorize this classification system, but it is helpful to know how it works.

Here's an outline of the major subject areas in the LC system:

A - General works  M - Music
B - Philosophy, Psychology, Religion N - Fine arts
C - History - Auxiliary sciences P - Language and literature
D - History (except U.S.) Q - Science
E - General U.S. history R - Medicine
F - Local U.S. history S - Agriculture
G - Geography, Anthropology, Recreation T - Technology
H - Social sciences U - Military
J - Political science V - Naval science
K - Law Z - Bibliography and Library science
L - Education  

A second letter is then used to further subdivide subject areas. For example, the "G" subject category is divided into these subdivisions:

G Geography
GA Mathematical geography
GB Physical geography
GC Oceanography
GF Human ecology
GN Anthropology
GR Folklore
GT Manners and customs
GV Recreation

Each subject subdivision is then further divided into specific topics using numbers. This combination of subject areas (letters) and numbers is called the call number for that book. 

Dewey Decimal Classification

The Dewey Decimal Classification system is used for the Curriculum and Juvenile Collections. These book collections are used mainly by education students. This system uses numbers to group books by subject:

Dewey Decimal Classification System
000 Generalities
100 Philosophy and Psychology
200 Religion
300 Social Science
400 Language
500 Natural Sciences and Mathematics
600 Technology (Applied Sciences and Medicine)
700 Arts, Entertainment, and Sports
800 Literature and Rhetoric
900 Geography and History

Dewey works very similarly to Library of Congress, but it starts with numbers instead and is grouped into a smaller number of broader subjects. This makes it much more suitable to Juvenile Collections rather than the much larger amount of subjects at university libraries. You will definitely see Dewey being used often in Public Libraries as well.

Finding Books in the Library

Call Numbers

Call number on book spineThe Sherratt Library assigns each library item a unique call number according to the Library of Congress Classification system. A call number is a unique "address" for an item. You need this call number to find a book in the library. The call number is available from the library catalog, and is printed on the spine or cover of each book.

A call number begins with one or two letters. The call number for the book shown here is: GV 989 .A52 

Shelf Order

Books are placed on shelves according to their call numbers. Books are shelved from left to right according to the LC system. Books are arranged first by the alphabetical top row, then by the number in the second row, finally by the alphabetical letter and decimal number in the third row:

So GA goes before GV, and just G would go before GA. The 989 is a whole number, so look at it in completion, with 99 being smaller than 989.

Remember, when using decimal numbers, numbers will be smaller to larger, left to right! (For example, when comparing .A4010 with .A52 by position, the 4 is smaller than 5 so .A4010 comes first.)

If you understand how the LC system works in the Sherratt Library, you'll be able to walk into the Marriott Library at the University of Utah, or the Harold B. Lee Library at Brigham Young University, or the Widener Library at Harvard University and find books!

Collection Codes

Collection codes are identifiers added at the beginning of the call number to indicate a particular collection:





Curriculum Collection

3rd Level


Instructional Media

3rd Level


Juvenile Collection

3rd Level


Main - Oversize

3rd Level


Reference Collection

1st (Main) Level


Special Collections

Garden (Fountain) Level

Locating books

When you've found a book in the library catalog, be sure to note:

  • Call Number

  • Collection

  • Availability for checkout

With this information, you can go to that collection, and to the shelf where it is located. For example, suppose you want to find the book Roughing It, written by Mark Twain. It is in the Main Collection on the Second floor, call number PS 1318 .A1 

As you move through the book shelves, check the signs on the wooden ends of the  shelves. Notice that the call number falls within the range of the shelf in this picture.

As you go down this aisle, look at the spine labels on the books. You see there are several books labeled PS 1318. Then look for the .A1 portion of the call number. Notice that there are other books on this shelf authored by Mark Twain.

TIP: Once you find an item on the shelf, browse items nearby. Books are shelved according to subject, and you may find something else useful. 

What if a book is missing?

If the library catalog indicates that an item is checked in but you cannot find it on the shelf, follow these steps:

  • Double-check the collection and call number.

  • Look on nearby shelves to see if the item has been incorrectly shelved.

  • Look on the red return shelves near the area.

  • Ask someone at the Circulation Desk if the item is on a re-shelving cart.

Hint: When you take an item off the shelf, don't put it back yourself. Instead, put it on a red shelf so that a librarian can make sure it is returned to its correct location.

Reciprocal borrowing

As a student at SUU, you can use your SUU ID to borrow books from other academic libraries in Utah.