Reading call numbers
To be able to efficiently read Library of Congress (LC) call numbers is quite a skill. This tutorial was created to help library users uncover the mysteries of call number reading.
Let's start with a sample call number: QE534.2.B64
Call numbers can begin with one, two, or three letters:
Numbers after letters
Cutter number
Shelving and Locating
Items are shelved by call numbers - in both alphabetical and numerical order. The letters at the beginning of the call number are alphabetical. The numbers immediately following are in basic numerical order, i.e. 5 then 6, 50 is after 49 and before 51, and 100 is after 99. Thus,
QD 1 |
QD 2 |
QD 3 |
QD 29 |
QD 30 |
The Cutter numbers (A3, A31, Z4, C3, and A2 in the above example) are sorted first by the letter and then by the number as a decimal. For QD 1 A5 think of it as being QD 1 A 0.5, for QD 1 A332, read QD 1 A 0.332. Therefore,
QD 1 |
QD 1 |
QD 1 |
QD 1 |
QD 1 |
QD 1 |
QD 1 |
Dates, volume and issue numbers, copy numbers, and other annotations are like an additional Cutter number but are shelved by basic alphabetization (numbers alone come before letters):
Q 10 |
Q 10 |
Q 10 |
Q 10 |
Q 10 |
QD 1 |
QD 1 |
QD 1 |
QD 1 |
This section contains examples of call numbers. Please look carefully at these examples; some of them may require closer inspection than others.
The following example contains three call numbers that are very similar except for one difference.
QC 981.8 |
QC 981.8 |
QC 981.8 |
You’ll notice that the only difference in these call numbers is the date. Remember that “nothing comes before something.” That is why QC 981.8 .G56 G578 comes before QC 981.8 .G56 G578 2002, etc.
Is the next example in the correct order?
N 6537 |
N 6537 |
N 6537 |
N 6537 |
The example is in the correct order. If you thought there was an error, chances are good that your confusion was caused by the Cutter numbers. The Cutter numbers are easy to confuse as being whole numbers. It is also easy to get "tunnel vision" when reading call numbers and neglect the alpha portion of the Cutter numbers. Here is the example again with the potentially confusing Cutter numbers in bold.
N 6537 |
N 6537 |
N 6537 |
N 6537 |
Remember that Cutter numbers are always read as decimals. Which call number below is out of place?
M 1010 |
M 1010 |
M 1010 |
M 1010 |
Did you find the book that is out of place? Look carefully at the bold Cutter numbers below.
M 1010 |
M 1010 |
M 1010 |
M 1010 |
Because we read Cutter numbers as decimals, these two books need to be switched to look like the following:
M 1010 |
M 1010 |
M 1010 |
M 1010 |
Cutter numbers can be very tricky....
It is very important to take your time when shelving and to look carefully at every aspect of a call number.
Take a look at the following call numbers and decide if they are in the right order. What are the differences between each call number?
PN 197.52 |
PN 197.6 |
PN 197.649 |
PN 197.68 |
They are in the correct order. The only difference is in the subject number lines. Now look at the next example. Are the call numbers in the right order? What is the difference between each of the call numbers?
Z 1003.3 |
ZA 1003.3 |
ZA 1003.3 |
These are also in the correct order. The difference between the first call number and the other two is that the first one contains Z while the other two both contain ZA. The difference between the second and the third call numbers is the copy number. It is important to pay careful attention to the small details. It can be very easy to pass over an incorrectly shelved book when you do not carefully inspect the entire call number.
The following example is ordered incorrectly. How should they be ordered?
DA 247.3 |
DB 766 |
DB 766 |
DB 766 |
DG 247.1 |
DC 325.5 |
The correct order is as follows:
DA 247.3 |
DB 766 |
DB 766 |
DB 766 |
DC 325.5 |
DG 247.1 |
Review
K 558 1997 |
K 558 2008 |
K 558 1977 |
K 564 2000 |
K 564 2000 |
All USask Library locations use the alphanumeric Library of Congress Classification (LCC) System. This system allows us to arrange materials next to each other on the shelves that are about the same or similar subjects. As a Casual Library Assistant 1, part of your responsibility will be to use this system to shelve books and ensure that the shelves are properly ordered. This guide will teach you how to use the LCC system to shelve books, shelf-read, and to perform general stack maintenance.
The LCC system allows books to be arranged by subject into 21 subject classes. Each book is assigned an alphanumeric call number based on its subject matter.
For a detailed look at the LCC Outline, click here.
(This guide was adapted from the Library of Congress Classification LibGuide, by Joseph E. Petta, Passaic County Community College Library. It has been edited for content.)