Universal Decimal Classification

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Library cataloging and classification
main topic

The Universal Decimal Classification (UDC) is a library classification system that was developed by the Belgian bibliographers Paul Otlet and Henri La Fontaine at the end of the 19th century. It is an extension of the Dewey Decimal Classification (DDC) system and is used in libraries around the world.

History

The UDC was first published in 1905 as an adaptation of the Dewey Decimal Classification. It was designed to be more flexible and detailed, allowing for the classification of a wider range of subjects. The system has been continuously revised and updated to accommodate new fields of knowledge and changes in existing fields.

Structure

The UDC uses a combination of numbers and symbols to represent different subjects. The main classes are divided into ten categories, each represented by a single digit from 0 to 9. These categories are further divided into subcategories using decimal points. For example, the number 5 represents Science, while 51 represents Mathematics.

Main Classes

• 0 - Generalities
• 1 - Philosophy and Psychology
• 2 - Religion
• 3 - Social Sciences
• 4 - Language and Linguistics
• 5 - Science
• 6 - Technology
• 7 - Arts and Recreation
• 8 - Literature
• 9 - Geography and History

Features

One of the key features of the UDC is its ability to express complex subjects through the use of auxiliary tables and symbols. This allows for the creation of compound numbers that can represent multi-faceted subjects. For example, a book on the history of mathematics in the 19th century could be classified using a combination of numbers from the history and mathematics categories.

Usage

The UDC is used in libraries around the world, particularly in Europe and Asia. It is especially popular in specialized libraries and information centers that require a more detailed classification system than the DDC.

Related Pages

• Library classification
• Dewey Decimal Classification
• Library of Congress Classification
• Paul Otlet
• Henri La Fontaine

See Also

• Information science
• Bibliography
• Cataloging