Dewey Decimal Classification

System for organizing the contents of a library based on the division of all knowledge into 10 groups. Each group is assigned 100 numbers.

Subdivisions eventually extend into decimal numbers; for example, the history of England is placed at 942, the history of the Stuart period at 942.06, and the history of the English Commonwealth at 942.063. The system was first formulated in 1873 by Melvil Dewey. Many libraries add a book number created from the Cutter, or Cutter-Sanborn, Tables, which further specify author and genre. The Library of Congress Classification has largely replaced the Dewey system.