The Dewey Decimal Classification (DDC) system, like the Library of Congress Classification System, is a way of organizing knowledge and making it accessible. Although the DDC is the most widely used classification system in the world, it is most commonly found in public libraries and in curriculum collections. The system is maintained by the Library of Congress and is constantly updated. At WCSU, the Juvenile (Children and Young Adult) Non-Fiction, Poetry and Folk Literature sections of the Curriculum Collection are organized according to the DDC System. The Juvenile Fiction section is organized according to a modified Dewey Decimal Classification System, using the first 1-2 letters from the author last name along with a cutter number also corresponding to the author name. This modified Dewey system ensures that all books with the same author name are shelved together.

The DDC is referred to as a faceted system, as each additional decimal place, or facet, indicates a more specific subdivision of a main topic. The longer the number, the more specific the nature of the topic.

A. The Ten Classes of Knowledge

The DDC is divided into ten main classes, organized by disciplines or fields of study. These are intended to cover the entire world of knowledge. All other subdivisions follow under each discipline or field of study. This ensures that each book will have its own unique call number and place on the shelf.

B. Subdivisions of the Ten Classes

Each main class is further divided into ten divisions (known as the "hundred" divisions), and each division into ten sections. Each subdivision indicates a greater level of specificity. The length of each notation indicates a more specific field of study.

One of the best ways to learn to read the DDC numbers is by reviewing and comparing examples of books in different subject areas. The following examples are books from the WCSU Curriculum Collection.

Example 1

Ryan, Pam Munoz. When Marian Sang. Juv. Coll. 782.1 R957w

Focus on the 782.1 number, and disregard the rest of the call number for now.

The first digit in each three-digit number represents the main class.

7 00 represents fine arts

The second digit in each three-digit number indicates the division.

78 0 represents music

The third digit in each three-digit number indicates the section.

782 represents dramatic music & production of musical drama

A decimal point follows the third digit in a class number. Digits following the decimal point indicate further specificity.

782.1 represents opera

Example 2

MacDonald, Fiona. Inside Story: A Medieval Castle. Juv. Coll. 940.1 M145M

900 represents general geography & history

940 represents general history of Europe

940.1 Middle Ages 476-1453

Example 3

Wilkinson, Philip. Buddhism: Explore the Teachings and Traditions of this Ancient Religion. Juv. Coll. 294.3 W6596b

200 represents religion

290 represents other & comparative religion

294 represents religions of Indic origin

294.3 Buddhism

Example 4

Hartley, Karen. Hearing in Living Things. Juv. Coll. 573.8 H255.3h

500 represents pure sciences

570 represents life sciences

573 represents physical anthropology

573.8 Nervous & sensory systems

Example 5

Gadi Mirrabooka: Australian Aboriginal Tales from the Dreaming. Juv. Coll. 398.2 G1175a

300 represents social sciences

390 represents customs & folklore

398 represents folklore

398.2 folk literature

Example 6

Simons, Seymour. Oceans. Juv. Coll. 551.46 Si55o

500 represents pure sciences

550 represents earth sciences

551 represents geology, hydrology, meteorology

551.4 represents geomorphology & hydrosphere, water

551.46 Oceans, oceanography

Examples of Science Call Number Structure

Science and Technology

500 represents natural sciences and mathematics.

500 is used for general works in the sciences, 510 for mathematics, 520 for astronomy, 530 for physics.

530 is used for general works on physics, 531 for classical mechanics, 532 for fluid mechanics, 533 for gas mechanics.

Applied Sciences

6 00 Technology (Applied Sciences)

63 0 Agriculture and related technologies

636 Animal husbandry

636.7 Dogs

636.8 Cats

• Every Dewey Decimal (DDC) call number begins with three numbers (003 is never written as 3 in DDC), some with decimal numbers followed by various letters, and/or number combinations.
• Numbers to the left of the decimal point in Dewey call numbers are whole numbers. Therefore, 015 comes before 150.
• Numbers to the right of the decimal point in DDC call numbers are decimal numbers. Therefore, 970.13 comes before 970.3.

Examples:

468.642 Ab2a

468.642 Al1c 1995 - Al comes after Ab

970 T16n - 970 (970.000) is a large number than 468.642

970 We 37 - We comes after T alphabetically

970.01 C72: - 970.01 is larger than 970 (970.0000)

970.13 B61d - 970.13 is larger than 970.3

970.3 B36o - 970.3 (970.300) is larger than 970.13 (970.130)

A call number in the Dewey Decimal System is read much like an LC call number, except for the fact that it does not begin with a set of letters.

1) The first line of the call number is arranged in strict numerical order.

2) The second line of a Dewey call number is also called a “cutter number”. It is read the same way as an LC call number, first alphabetically and then numerically as a decimal. It corresponds to the author name. You may also find “double cutter” numbers.

3) Additional lines may also be added to indicate a new edition of a book or an additional copy. All dated editions are filed after undated editions and in chronological order.