December 26, 1931: Melvil Dewey, the inventor of the Dewey Decimal classification system used today in libraries around the world, died at the age of 80.

Melvil Dewey’s love of efficiency is clear in the Dewey Decimal System, which is used in libraries worldwide today. Photo credit: Elizabeth Howell

Dewey’s invention – created when he was just 21 years old, in 1876 – revolutionized library cataloging. The numbering system categorized books in relation to each other. Before, books in libraries were numbered according to their physical location. The old system made it hard for libraries to move the books, as the numbering system would change.

Also in 1876, Dewey helped found the American Library Association. He served as its secretary until 1890. Dewey also was passionate about simplifying spelling; he shortened his first name from “Melville”, and for a while, he spelled his last name as “Dui.”