What Is the Dewey Decimal System and Why Do Libraries Use It?

The Dewey Decimal System is one of the most recognized book classification systems in the world. Developed to bring order to the growing number of books in libraries, this system has become a standard in organizing knowledge.

But how exactly did it come to be, and is it still used today at our local libraries? Let’s take a closer look at the Dewey Decimal System, how it was invented, why it remains relevant today.

The Origins of the Dewey Decimal System

The Dewey Decimal System was invented by Melvil Dewey in 1876. Dewey, a librarian and education reformer, recognized the need for a structured, scalable method to categorize books so they could be easily located and returned to their proper place.

His innovative idea involved dividing all human knowledge into ten main classes, each identified by a three-digit number. These were then subdivided into more specific topics using decimals—hence the name Dewey Decimal.

At the time, libraries often used rudimentary or inconsistent filing systems. Dewey’s structured, numerical approach revolutionized library science and offered a unified way to sort books based on subject matter.

How the Dewey Decimal System Works

The Dewey Decimal Classification (DDC) organizes books into ten broad categories:

• 000 – General works, computer science, and information
• 100 – Philosophy and psychology
• 200 – Religion
• 300 – Social sciences
• 400 – Language
• 500 – Natural sciences and mathematics
• 600 – Technology (applied sciences)
• 700 – Arts and recreation
• 800 – Literature
• 900 – History and geography

Each category can be further divided using decimals, allowing for extremely detailed classification. For example, a book on marine biology might be cataloged as 578.77, providing a precise location within the library’s collection.

Do Libraries Still Use the Dewey Decimal System?

Yes, many public and school libraries around the world still use the Dewey Decimal System today, which includes our Jacksonville libraries. While some academic and specialized libraries have adopted other systems like the Library of Congress Classification (LCC), Dewey remains widely used due to its simplicity and accessibility for general users.

Some libraries have tried experimenting with bookstore-style shelving systems, but many have returned to Dewey for its clarity and universal consistency. Even in the digital age, the Dewey system helps structure online catalogs and digital archives.

Interesting Facts About the Dewey Decimal System

• Melvil Dewey was a reformer who even tried to simplify English spelling—he signed his name “Melvil Dui” in later years.
• The Dewey Decimal System is maintained by the Online Computer Library Center (OCLC), which updates the system regularly to reflect new areas of knowledge.
• It’s been translated into over 30 languages and is used in more than 135 countries.
• Each book’s Dewey number includes a “cutter number,” which further organizes items by author or title within the same subject category.
• Libraries sometimes add their own letters or tags to the Dewey number to assist with shelving by genre or local interest.

Why the Dewey Decimal System Still Matters

Even in an era dominated by digital search engines and databases, the Dewey Decimal System remains a cornerstone of organized information. It’s intuitive, scalable, and adaptable—perfect for guiding readers through the vast universe of knowledge.

Whether you’re browsing a library shelf or exploring an online catalog, understanding the Dewey Decimal System helps you locate information faster and appreciate the method behind the shelves. It’s a testament to how one man’s organized mind reshaped the way we access knowledge.