American librarian Melvil Dewey, born Melville Louis Kossuth Dewey, in Adams Center, N.Y., on Dec. 10, 1851, d. Dec. 26, 1931, is best known as the inventor of what came to be called the Dewey Decimal System of Classification, which is used in most local and school libraries to catalogue books. Devised in 1876 as a system for small libraries, it has the advantage of a limited number of general categories and short call-numbers. The system is based on ten classes of subject (000-999), which are then further subdivided. Dewey also promoted the use of the metric system, helped found the American Library Association in 1876, and edited Library Journal (1876-81) and Library Notes (1886-98). When Dewey created Columbia University's School of Library Economy in 1887, he began the field of library science in the United States.