Library Student Workers: Library of Congress Call Numbers

Online Practice Test

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Library of Congress Call Numbers & Shelving

Did you know? Most academic libraries don't use the Dewey Decimal System. They use a classification system called The Library of Congress Classification System, which was developed in Washington D.C at the Library of Congress. (Go figure.)

Introducing the Library of Congress System

Shelving books correctly must absolutely be done each and every time. Since a mis-shelved book is a lost book,
Correct shelving is crucial to the academic support we provide for our clients. Remember, you may be asked to look
for lost books in the future, so let’s do it right today! Here are some basic shelving rules to help you get familiar with our system.

Murrell Library and Commons  use the LC (Library of Congress) classification system to organize out collections. Our cataloger assigns each item a unique call number that, like a street address, tells us where the item should be located in the library. The LC system uses the beginning letters and first line of numbers to indicate the subject of the book. As you might expect, the letters are ordered alphabetically. For example, the letter D comes before K, and so forth. Similarly, the letter L comes before LA, which comes before LB.

The numbers immediately following the first letter(s) are read as whole numbers. For example, 212 comes before 761 but after 115. Sometimes there are decimals in the first number. In these cases, the whole numbers are read as before, but the numbers following the decimal are read as decimals. These numbers follow a set pattern, starting with a letter or combination of letters assigned to a specific subject area. The next line is usually a number, followed by a line with a letter and a number, and so forth. We use alphabetical and numerical order, comparing each line until you find a difference, to put the call numbers in proper order.

EXAMPLES:

A book with a call number beginning with H will come before a book with a call number beginning with HB.This rule holds true throughout the call number, line by line.

When there are different editions or multiple copies of the same book, volumes in a set, or books in a series, the basic call numbers will be identical, but each one usually ends with a line indicating the copy number, the edition year, the volume, etc. These should be put in numerical or chronological order.

Again, simply compare line by line until the call numbers are different, and follow the rules for alphabetical, numerical, and/or chronological order. Note that indexes go at the end of a set on the shelf.

The line that starts with a decimal, usually the third line, is called a “cutter” number. It is a combination of a letters and numbers. File the letters alphabetically, but the numbers should be treated as a decimal point. This is a decimal point and it acts like a decimal point, which will affect the numerical order for all numbers following the decimal point, including numbers on subsequent lines.

In the first example above, .R27 comes before .R4 because .27 is a smaller number than .4. In the second example, .R7 M32 comes before .R7 M5 because .32 is smaller than .5.

If you find yourself having difficulty, there are some tricks you can use. The first one is to add zeros to the numbers after the decimal point to make the number of digits equal, and then it will be easier to see which number is actually smaller (remember the rules of mathematics dictate that adding zeros on the end of a number after a decimal point does not affect the value of that number… Imagine that .3 is really 300 and .123 is really 123. Therefore, you would shelve .123 before .3). Another trick is to go line by line UNTIL you reach the decimal point, and then go digit by digit, stopping as soon as you find a difference; the number that is smaller at this point will come first.

Some areas have special patterns. Again, remember the basic rules, and you should have little trouble. For example, books in the Juvenile collection follow the same principles outlined here, but there is a small “j” in front of the call number.