On the backs of all our books on the shelves you will notice a series of numbers.
These numbers are called call numbers. Call numbers are how we find books (or other items) on the shelf.
Just as you have a unique address where you live at home, each item has a unique address where it lives on the shelf.
The call number is made up of three different parts; prefix, dewey number and suffix.

The Prefix
The prefix tells you which collection an item belongs to.
AV - items belongs to the AudioVisual collection.
DVD - item belongs in the DVD collection.
FLC - item belongs in the Fiction collection.
LD - item belongs s in the Language Development collection.
PER- item belongs in the Periodical collection
REF- item belongs in the Reference collection
VID - item belongs in the Video collection
Items without a prefix belong in the general collection.

Dewey Numbers
The numbering system is based on the Dewey Classification scheme (also known as the Dewey Decimal System).
Each item is assigned a Dewey number and the number depends on the item's subject.
Dewey numbers divide humanity's knowledge into ten major subject areas spanning a range from 000 to 999. See below for full description.

The example of our book on the right broadly comes under the arts at 700.

Each major category divides into nine sub-categories spanning a range of 10 to 90.
e.g. 790 is recreational and performing arts.

Each sub-category is further divided into nine specialised topics ranging from 1 to 9.
e.g. 791 is public performance.

By adding decimals, the specialised topics are broken down even further.
e.g. 791.43 is public performance, motion pictures.
So our example to the right is categorised under arts>recreational and performing arts>public performance>motion pictures.

Thus the Dewey Decimal System is a hierarchical system, in which the arrangement of books on the shelves moves from the general to the specific.

Suffixes and volume numbers
The suffix gives the first three letters of the authors name. So if there are several books that belong at 791.43 in our example above, they are then filed alphabetically by the first three letters of the authors name.
e.g 791.43 AND comes before 791.43 DAW on the shelf.
Volume numbers are given after the suffix. e.g 791.43 AND:1 is volume 1 which comes before 791.43 AND:2 which is volume 2.