Understanding
Call Numbers
What are
call numbers for?
Each book in
the library has a unique call number. A call number is like an address:
it tells us where the book is located in the library. Call
numbers appear
Note that the
same call number can be written from
toptobottom, or lefttoright.
Alvernia College Library uses the Dewey Decimal System for call numbers. This system uses a combination
of numbers and letters to arrange materials by subjects.
What
do the parts of a call number mean?
Call numbers are basically divided into two parts:
 subject classification: series of numbers that represent the subject area
 author classification: series of letters and/or numbers that represent the
author or title of the information
Some call numbers have a third part for the year of publication or extra author
information.
Let's look at how we can interpret the call numbers of the book The Fly in the Cathedral by Brian Cathcart. The call number for this book is:
 The first number, 5, indicates the book is in the 500s, which is the field of natural sciences and mathematics
 The second number, 3, places the book in the 530s, which is the field of physics
 The third number, 9, places the book in modern physics
 The fourth number, .7, indicates the book is about atomic and nuclear physics
 The second line, C362, refers to the author Cathcart. Each author is assigned a unique number.
 The third line, 2005, tells us the publication date
The meaning of the call numbers illustrates how items about similiar topics are grouped together on library shelves. When you find a book on your topic, check the books on the same shelf; you may find additional relevant books.
How do I use a call number to find an item?


It is important to note the entire call number. Then you need to find each
part of the number in turn.
For example to find the book
A short history of Ireland, by Richard Killeen with the call number
 Locate the first three digits
 Locate any digits following the decimal point. Remember that it is a decimal
system, so 941.7081 comes after 941.68
 When you have located the number in full, look for the letter, then
the next set of numbers
 Check that the last letter and number are correct, to make sure you have
the right book and edition
Summary
 items on the same topic are shelved together
 every part of the number is important for locating an item
 work through the call number systematically to find the item
