# Understanding Call Numbers

## Understanding Call Numbers

A call number is the address of
the book in the library collection.

 Here are some examples
 QE 352 B64 1999
 TK 7872 F5 H797 1993
 RC 41 G35 1999 v.4
 LB 2825 S58 Suppl.

1.  The first line of a call number may begin with one, two, or three letters. These letters should be read alphabetically. A call number that begins with A is shelved before one that begins with B, C, etc.; and a call number that begins with QE is located somewhere before the one that starts with QL.

 QE

before

 QL

2.  The second line

of a call number is made of a number that may have one or more digits.
This line is read numerically. A call number with a smaller number in its second line is
placed before one that has a larger number for its second line:

 HD987

before

 HD1001

3.  The third line

is the trickiest part of the call number: The letter is shelved alphabetically, and the number following the letter is treated as if it were preceded by a decimal. Thus:

 QE 352B64 1999

before

 QE 352C85 1999

But, the tricky part of the 3rd line of the call number is that its numerical component is
. Thus, these examples are in correct call number order:

 QE 352 C444 1999

before

 QE 352 C64 1999

before

 QE 352 C7 1999

before

 QE 352 C754 1999

This makes sense if you read the numbers as decimals!

 0.444

before

 0.64

before

 0.7

before

 0.754

4.  The final lines
of the call numbers may include dates, volume indicators, issue numbers,
copy numbers, and other annotations such as supplement or index specifiers. These
annotations are read after the call number.

If you still can't find the book you want, please ask for help at the Reference Desk,
Library North, 1st floor.