All books in the Library are shelved in call number order according to the Library of Congress system. This system flows both alphabetically and numerically, using multiple lines.
FIRST LINE
The first line will have from one to three letters, and indicates order alphabetically, the same way as a dictionary. For example:
A | AA | AB | AC | AD | AE | AF | AG | AH | AJ | AK | ….. AZ |
Not all the letters will be used. These examples are to give you a rough idea of how the system works. Here is an example of the first line with three call numbers.
KFA | KFB | KFC | KFD | …… KFX |
SECOND LINE
Next, when the first line of the call number is identical, then the second line is used to determine order numerically. The second line is a whole number.
For example:
PS | PS | PS |
65 | 585 | 3515 |
(The second line of the call number PS 65 is read as sixty-five.)
(The second line of the call number PS 585 is read as five hundred, eighty-five.)
(The second line of the call number PS 3515 is read as three thousand, five hundred and fifteen.)
SECOND LINE WITH A DECIMAL
Sometimes, the second line which is a whole number is followed by a decimal. The whole number comes first, followed by the decimals, which go in order from smallest to largest. You must match the decimal number-for-number making sure the smallest numbers go first.
PS | PS | PS |
3515.115 | 3515.12 | 3515.5 |
These books would go on the shelf after any books with the PS 3515 call number.
THIRD LINE
If the first two lines are identical, then you should go to the third line to determine call number order. The third line ALWAYS begins with a decimal point followed by a letter, and then one or more digits. Like the previous example, the numbers go from the smallest to the largest, matching number-for-number.
Look at the following example:
PS | PS | PS | PS | PS | PS |
3515 | 3515 | 3515 | 3515 | 3515 | 3515 |
.M112 | .M12 | .M135 | .M2 | .M213 | .M23 |
With this example, it would appear at first that "2" should come before "112." However, if you compare the first digit after the M, “1" comes before “2", so this determines the order. Remember, the third line is NOT read as a whole number!
FOURTH LINE
The fourth line is a continuation of the third line. It should be read alphabetically, and then as a decimal. If the first three lines of the call number are the same, then you must go to the forth line.
For example:
PS | PS |
3515 | 3515 |
.R3457 | .R3457 |
U137 | U17 |
It would appear at first that "17" should come before "137." The first digits after the U, “1” is the same for both yet the next digit “3” is before “7,” so this determines the order. Remember, the fourth line is NOT read as a whole number!
NOTHING COMES BEFORE SOMETHING RULE:
The call number with less information goes before the one with more.
For example:
PS | PS |
3515 | 3515 |
.R3457 | .R3457 |
2006 | U137 |
2003 |
Another Example:
If two call numbers are the same, except that one has an additional line beyond the other, the call number with more information is considered to be higher.
For example:
PS | PS |
3515 | 3515 |
.R3457 | .R3457 |
U137 | U137 |
2006 |
OTHER ODDITIES:
If you see a call number with the third line that looks like a zero, it is really the letter O. Example, PS 3515 .O17
If you see a call number with the third line that looks like a one, it is really the letter I. Example, PS 3515 .l17