The Dewey Decimal System: Classification Numbers

The Dewey decimal system coordinates materials on the same subject and on related subjects to make items easier to find on the shelves by using a combination of letters and numbers.

 The Dewey system has ten main classes, which are listed below.

• 000 Generalities 
• 100 Philosophy and Psychology
• 200 Religion
• 300 Social Science
• 400 Language
• 500 Natural Science and Mathematics
• 600 Technology (Applied Sciences)
• 700 Arts
• 800 Literature
• 900 Geography and History

Each of the above classes has ten divisions. These divisions are further divided--and then further divided. Each division becomes more specific. For instance, the more numbers, the more specific the subject. In this way, the Dewey classification system progresses from the general to the specific. 

The Dewey Decimal Classification (DDC) is used by most libraries to categorize its material. The call number is composed of two parts: the Dewey Decimal Classification and the Cutter Number.

Call Numbers

Once you know the call number for an item, which you determine by searching the online catalog, ISAAC, you can locate the item in the library. Call numbers serve two main functions within a library:

·        They tell you where an item is located by providing a unique "address" for every item within a library, and

·        They tell you what subject area an item is assigned to. This allows you to browse the shelves around a particular item to find other materials on the same or similar subjects.

Cutter Number

A cutter number consists of the first letter of the author’s last name and a series of numbers that allow books to be placed on the shelves alphabetically.

Cutter numbers can be used to make a distinction between books by the same author. A lowercase letter, normally the first letter of the title of the book is assigned.