Dewey Decimal System Day - December 10
Sun, Dec 10, 2023

Dewey Decimal System Day

Dewey Decimal System Day is celebrated on December 10th in the United States. This unique holiday is dedicated to Melville Louis Kossuth Dewey – the inventor of the decimal classification system, and the most popular librarian in the world. Let’s take some time to learn more about him and his incredible life!


Melville Louis Kossuth Dewey was born in New York State in 1851. He was a bright child with a passion for mathematics, and at the age of 15, he left school to teach in elementary grades. In 1870, Dewey enrolled in college and began his career as a librarian. It was during this time that he came up with the idea of the decimal classification system – and the library council approved of it. The decimal system was published to the general public in 1876, and its principle is to distinguish ten different classifications, which in turn are also divided into 10 departments. Amazingly, no one had thought of this system before Dewey – it’s simple and useful, and today it is used in the largest libraries in the world.

Interesting facts

  • Despite receiving a master’s degree in mathematics, Melville remained in the position of librarian.
  • Many consider him the founding father of the library profession, as his approach to business was highly professional. In 1887, he opened the first school dedicated to teaching librarianship.
  • Dewey chose a wife to match – the girl was the responsible librarian at Amhert College.

How to take part

Head to your nearest library and take a look at how the books are organized. Talk to the staff and find out their thoughts on the system. Share information about the holiday with others – as it turns out, not everyone knows about it!

When is Dewey Decimal System Day celebrated in 2023?

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


Weekday Month Day Year
Sunday December 10 2023
Tuesday December 10 2024
Wednesday December 10 2025
Thursday December 10 2026

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