Far North Bible College

How to Find Books by Call Number

Andrus Memorial Library uses the Library of Congress (LC) classification system for organizing and shelving books. Each book as a unique "call number" composed of letters and numbers, which is used to determine the book's placement on the shelf, and to group it among other books on the same subject.

LIBRARY OF CONGRESS CALL NUMBERS ARE MADE UP OF THREE LINES:

• The first line is a letter or letters arranged alphabetically which represent the subject area.
• The second line is a whole number arranged numerically.
• The third line is a combination of a letter and number arranged alphabetically and then numerically.
• Sometimes there is an additional line with a letter-number combination (which is arranged in the same way as the third line), and sometimes there is a publication year on the bottom line of the call number.

For example, here is a typical LC call number:

To find the above book with this call number on the shelf, you would first look for the shelves with books with call numbers starting with Q. Books are arranged on the shelves by call number beginning with books with call numbers starting with A and ending with books with call numbers starting with Z. At the end of each set of shelves are labels identifying the call numbers of the books on those shelves.

The order of different call numbers is determined by comparing each line of each call number starting from the top and then going down until you find a difference between them. If the first lines of two call numbers are the same, check the second lines. If both the first and second lines are the same, compare the third lines, and so on.

Continuing with our example, once you find the books with call numbers starting with Q, follow the call numbers of the books and you will then see books with call numbers starting with QA and then books with call numbers starting with QB. Thus, call numbers are arranged first by the letter or letters on the first line in alphabetical order.

Note: A decimal point may be included at the beginning of the third line (as in .H27, .M15 and .M3 below) but, whether or not a decimal point is included, the order is the same.

Let's continue to look for the call number in our example:

Once you find the call numbers starting with QB, look at the numbers on the second row of the call number. Follow them numerically until you find 44. The second line of an LC call number is arranged numerically.

Now you've found the books that start with:

If there is only one book that has a call number beginning with those two lines, you don't have to look any farther to figure out the order. When you find many call numbers with the same first two lines, however, you need to compare the third lines of each one. Understanding the order of the third line, with the letter-number combination (M65, in our example) can be a little confusing. The combination is read first alphabetically by letter and then numerically by the number. The tricky part is that the number is a decimal number.

First find the letter (M, in our example) alphabetically. If all of the letters are different, the order is decided just by the letters. If there are any call numbers with the same first two lines and with the same letter at the beginning of the third line, you then have to compare the numbers following the letter.

The number after the letter (65, in the example) is a decimal number. This is where many people get confused. Look closely at the following call numbers which are in correct order:

If you remember that the numbers in the third row after the letter are decimal numbers, the order will make sense.

If you have trouble with decimal numbers, remember that there are imaginary zeros at the end of all decimal numbers.

So in the example, you can see why M125 comes before M15 if you put a zero after the 15. Another way to understand this is to look at one number at a time. For example, the first number in both M125 and M15 is 1, but the second number in M125, which is 2, comes before the second number in M15, which is 5.

A decimal point may be included at the beginning of the third line (as in .H27, .M15 and .M3 above) but, whether or not a decimal point is included, the order is the same.

If there is a fourth line with a letter-number combination (and all previous lines of multiple call numbers are the same), that line would be arranged in the same way as the third line. For example:

Look at the following examples of correct call number order. Be sure that you understand why they are in the order shown. If you do not understand, be sure to ask a librarian to explain it to you.

Adapted from CSM Library http://smccd.net/accounts/karas/english/numbers.html

• Convert the call number from the catalog display to a vertical form (as it appears on the spine or lower front cover of a book).
• Example: BV3775.S68P75 becomes