Just what do all those numbers on the spines of library books actually mean?
Are they just randomly assigned?
Is it a running number or do they indicate when the library purchased that item? Why are there letters at the end of the number? What does that mean?
How come some books only have letters and no number?
Well be confused no longer!!!
Over the series of Call Number Confusion posts, I will attempt to unravel the mystery that is the library collection and call numbers.

Where do the numbers come from?
Call numbers are not randomly assigned. They are created using something called the Dewey Decimal Classification System.

Melvil Dewey

Developed by Melvil Dewey in 1876, the Dewey System organized all of the world’s knowledge into Ten basic classes, called Hundreds. Each of these Hundreds are then broken into ten more areas, the Tens, and those are broken down into ten more areas, the Units, then down to the decimal places.
What this means is that every part of the call number actually means something!The numbers that make up a book’s Call Number actually tell us something about the content of that book and ensures that similar material is shelved around it.
For example, the 900s deal with Geography and History and 94 is the number for Australia, therefore 994 would be the location for Australian History! 

Australian history books – 994.4

  
But what about those letters?
They are  taken from the Author’s surname or the titles and are used as a way to distinguish one book from another that shares the same Dewey Number. After all, there are going to be a lot of books on gardening or computing.

The next post in this series will begin our in-depth look at the call numbers used here at the Tea Tree Gully Library, starting a the beginning of the collection: 001-099!