Dewey Decimal System Day

Dewey Decimal System Day is on December 10th in the United States. This unique holiday honors Melvil Dewey—the inventor of the Dewey Decimal Classification and one of the most influential figures in library science. Let’s learn more about his remarkable life!

History

Melvil Louis Kossuth Dewey was born in New York in 1851. A gifted student with a passion for order and mathematics, he left school at 15 to teach in elementary grades. In 1870, he became a librarian and devised a revolutionary decimal classification system to organize books. Published in 1876, Dewey’s system divides all knowledge into ten broad classes, each further subdivided by tens—an elegant solution never before conceived. Today, it remains the standard in libraries worldwide.

Interesting Facts

• Although he earned a master’s degree in mathematics, Dewey devoted his career to library science.
• Often called the “father of modern librarianship,” he founded the first library school in 1887 at Columbia University.
• He married Emily Fox, who was the head cataloger at Amherst College, sharing his professional dedication.

How to Take Part

Visit your local library and explore how books are shelved by Dewey’s system. Speak with the librarians about its benefits and share this holiday with fellow book lovers!

When is Dewey Decimal System Day in 2025?

Dewey Decimal System Day is observed on December 10 each year.

Observations