Deweydesimaalijärjestelmään

Deweydesimaalijärjestelmään, commonly known as the Dewey Decimal System, is a library classification system. It was developed by Melvil Dewey in 1876. The system organizes library materials by subject. It uses ten main classes, each represented by a three-digit number. These classes are further divided into more specific subjects using decimal points.

The ten main classes are: 000 Computer science, information and general works; 100 Philosophy and psychology; 200 Religion; 300 Social sciences; 400 Language; 500 Science; 600 Technology; 700 Arts and recreation; 800 Literature; and 900 History and geography. For example, books on biology would be found in the 500s, specifically within the 570s for biology. Books on American history would fall under the 900s, typically in the 973s.

This system allows for a logical arrangement of books on shelves, making it easier for patrons to locate materials on specific topics. Libraries worldwide use variations of the Dewey Decimal System. It provides a standardized method for categorizing and retrieving information. The system is continuously updated to accommodate new subjects and evolving knowledge.