The Dewey Decimal Classification System

A short guide to how many libraries are arranged

The Dewey Decimal Classification (DDC) is virtually universal in the UK public library system, as well as being used in most academic libraries. In the United States it is challenged by the Library of Congress system (LC), but is still very widely used. It is therefore a good idea to know how it works and therefore how best to find one’s way round a library that is classified accordingly.

The principle devised by Melvil Dewey in 1876 was that all knowledge could be divided into ten parts, each of which could also be divided into ten, and so on. An infinite number of subdivisions of knowledge was therefore possible, and so any book in a library could be assigned a classification number that placed it within a subject category. Books on the same subject would be given the same number and so be placed together on the shelves.

Dewey’s original ten classes were as follows:

000 Generalities

100 Philosophy

200 Religion

300 Social Sciences

400 Language

500 Pure Science

600 Applied Science

700 The Arts