Use DDC main classes

About DDC main classes and summaries

The 10 main classes provide a top level outline of the DDC. Each main class represents one of the major areas into which the DDC divides recorded knowledge. The numbers and captions of the main classes comprise the first summary of the classification system.
The DDC defines 10 divisions within each main class. The numbers and captions of the main classes and their divisions comprise the 100 divisions of the second summary.
Within each division, the DDC defines sections. The numbers and captions of the main classes, the divisions, and the sections comprise the 1,000 sections of the third summary.

Classify an item by moving from a generally relevant class to an appropriately specific subclass.
When classifying, avoid moving too quickly to a narrowly focused search for an appropriate class number. Traversing the DDC hierarchy from the top down helps you remain aware of the broader context of a subject as represented in the DDC.
Get an overview of the structure of the DDC and/or of a particular class, division, or section.

To	Do this
View divisions within a main class	At the Main Classes screen, click the hyperlinked caption for the class whose divisions you want to view.
View record for another division or section	In the hierarchy display at the top of a record, click the hyperlinked caption for the division or section you want.
Search WebDewey	At the top of the Main Classes screen or a record, the Search option button is selected by default. In the text box, type 1 or more words to specify the subject you want. If desired, select an index and then click Search. Default index: All Fields
Browse WebDewey	At the top of the Main Classes screen or a record, select the Browse option button. In the text box, type 1 or more words to specify the subject you want. If desired, select an index and then click Browse. Default index: Dewey Numbers
Return to Main Classes screen from record	In the hierarchy display at the top of a record, click the hyperlinked caption Main Classes.
View Tables screen	At the bottom of the Main Classes screen, click Tables.