Content taken from Ohio Library Council's orientation website with permission.
What's the address?
Every item in the library has its own address, the call number. Each part of the call number has a special meaning, for example:
A code indicating the physical location of the item is usually the first part of the call number (e.g. REF, CHILD, FIC, or VIDEO).
For non-fiction, the next part is the DDC classification number that places the item with other items on the same topic.
The final part of the call number is often a letter/number code for the author or title, making the whole call number a unique identifier. If there is more than one edition, the year may be added, and sometimes a volume number is needed.
The classification number is like a street name -- it gets you to the right area in the library. But just as there are many houses on one street, there are many library items with the same classification number (because the subjects are the same). You need the exact house number if you don't want to jog up and down the street, knocking on a lot of doors! In a library that's what the book number is for - to get you to the exact item.
Call numbers and the catalog record
The call number is part of the catalog record and is also marked on the item or attached as a label. People can understand the call numbers, but automated systems may use bar codes or RFID tags instead. Maybe before the end of this millennium, brain scan technology will make all this obsolete! Meanwhile you need to understand call numbers.
On the Catalog page, you looked up a few book records. At least two were non-fiction.