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

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

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 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.

Call Numbers

The 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:

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.