A Class Number is a number that a Library gives to a book so that it can be stored and found.
In this Library we use the Dewey Decimal Classification for our Class Numbers. You may see this number refered to as to as 'DDC' in our online catalogue.
If you've ever looked for non-fiction books in an Irish public library, then you've used the Dewey Decimal System to find those books.
Books are filed under Class Numbers, which act like an address so that every book can be found.
100: Philosophy and Pyschology
300: Social Sciences
700: Arts and Recreation
900: History and Geography