HOW TO READ THE DEWEY DECIMAL SYSTEM

The typical “call number” on an item, be it a book, audiotape, video, or other type of material, consists of three or four lines. The first line is a location code, the second is a subject designation, and the third is normally an author code. Occasionally you will see a fourth line which is generally a copy number, a volume indicator, or perhaps a date. Here is a sample:

1st line location UPLYNF 2nd line Dewey Y636.7 3rd line author SMI 4th line other info c. 2

The location code, in this case, stands for University Park Public Library Youth Non-Fiction. Each item has a location code, which tells the area in which the item can be found. A list of these codes is available at the library, but the catalog will indicate the proper place when you call up a specific title.

Sometimes the Dewey number has “J” or “Y” at the far left side. The letter means the item is at the “juvenile” or “youth” level. These materials are shelved separately from adult materials.

If an item does not have a Dewey number, it should have another designator: F for fiction, SS for short stories, B for biography.

Dewey numbers are usually subject classifications. Melville Dewey developed his classification scheme in the 1800s, using subjects like History, Religion, Pure Science, and the like. There are ten major sections. Each section is subdivided ten times, and each of these is subdivided again. A number is assigned for each of these sections.  Using the example given above, let’s examine the number.

 Y = youth
 6 = applied sciences and technology
 3 = agriculture
 6 = animals and husbandry

The decimal point allows further division. The “7” indicates that this book is about dogs. Each subject has its number, which puts the item in its proper place.

There are two rules for filing books:

1. One number at a time = This means you first look for the 600 area. Within that section you look for the 630s, then within that you look for the 636s, and so forth. UPPL only uses three places to the right of the decimal point.
    
2. Nothing comes before something = This means if the number does not have all the places available filled, as in the example above, you assume the numbers missing are zeros. Therefore, 636.7 comes before 636.72 or anything with another number attached.

If you have more than one book with the same Dewey number, look at the 3^rd line. This designates the author’s last name, usually. Exceptions are in biography, art books on a specific artist, and criticism books on a specific author. If two authors have the same last name, they are filed under the last name and then alphabetically by the first name. For example: Robert Smith would come before Tom Smith.

Please remember that if you cannot find what you are looking for, you can always ask a staff member or volunteer for help.