For most of us, it was Dewey with whom we first became acquainted in our local public library. DDC is based on the division of all knowledge into the following ten groups:

• 000-099: General Works
• 100-199: Philosophy and Psychology
• 200-299: Religion
• 300-399: Social Sciences
• 400-499: Language
• 500-599: Natural Sciences and Mathematics
• 600-699: Technology
• 700-799: The Arts
• 800-899: Literature and Rhetoric
• 900-999: History/Biography/Geography

DDC's overall structure is simple and repetitive. The ten arabic numbers comprise the only symbology used by DDC; they are the most universally recognized of all written symbols. Each main class is further subdivided into ten divisions, which are each divided into ten sections. Sections are ultimately divided further by decimal notation. Below appears a glimpe at an old friend:

                          CLASS               700              The Arts
                           DIVISION            720              Architecture
                            SECTION             725              Public Structures
                                                725.4             Industrial Buildings

The scheme was originally implemented in the Amherst College Library in 1873 and initially published "over 50 years ago" in 1876. Dewey borrowed heavily by W. T. Harris, who had successfully arranged the materials of the St. Louis Public Library with a similar scheme. Yet it is Dewey's name that endures.

The enduring success of Dewey results from several unique features:

• Its simple notation is idependent of language, thus allowing international application.
• It incorporates with great success a mnemonic system of repeaters. (e.g. "45" frequently designates "Italy,")
• Adheres to the principle of "number building."
• It is a self perpetuating corporation and remains self-published.

The above features have been made known to so many due to a combination of fortuitous timing and Melvil Dewey's considerable marketing talents. Today DDC is the most widely known and used classification scheme in the world.