Who is Dewey? And how do I get his number?

By Peggy Kindiger

According to Online Computer Library Center (OCLC), Melvil Dewey was an American librarian and educator in the late 19th and early 20th centuries.  He revolutionized the way libraries catalog and arrange books by devising a system to categorize different subjects.   This earned him the title, “Father of Modern Librarianship”.

The Dewey Decimal Classification system divides non-fiction subjects into ten broad categories ranging from 000 to 900:

dewey decimal system pic

To narrow down a particular category, the numbers are refined and decimals are added.  These are referred to as “call numbers”.  For example, books on science are found in the 500s.  Astronomy is classified as 520. A person wanting to study planets in our solar system would go to the section numbered 523.  And if Mars was of particular interest, the person would look for books labeled 523.43 as shown below.

new chart

Similar charts can be found online for all ten categories.


Other charts are available to make a search even easier.  Below is an example of a poster with subject suggestions and the corresponding Dewey numbers.

dewey decimal system pic 3
Hillhead Library, Glasgow, Scotland

Most public libraries use the traditional Dewey system, but some are changing to more modernized versions, or even to “Dewey-free” systems.  The BISAC (Book Industry Standards and Communications) system classifies books by keywords, similar to the way bookstores arrange their collections.  PIM (developed in the Netherlands) uses color coded pictograms combined with keywords to organize non-fiction materials.  Both systems are designed to make browsing easier for patrons and can work well in libraries with relatively small collections. So, if you wanted to find a book about German Shepherd dogs, you would first find the Pet section, then look for Dogs, then look for German Shepherds.

El Reno Carnegie Library will still be using the Dewey Decimal Classification for the foreseeable future.  If you have any questions about where our books are located, please ask one of our friendly staff.  Just say, “Talk Dewey to Me”!!!