A call number is like an address for a book. It tells you exactly where to go to find the book, or where the book should be returned. The call number is made up of letters, whole numbers, decimals, almost always a publication date, and occasionally a volume and/or copy number. This allows for each book to have a specific identity and location. One book’s identity/location cannot be confused with another book's identity/location.
For example, a library patron is looking for John Steinbeck's classic novel, The Grapes of Wrath. After the patron conducts a search in the LRC’s online library catalog:
1.) they find that several editions of the book are available at CVCC;
2.) they choose the Viking edition;
3.) they find this call number on the display record:
PS 3537 .T3234 G8 1967
On the spine of the book, the call number is arranged vertically by component part:
PS -Subject (alpha)
3537 -Subject (number)
.T3234 - first Cutter
G8 -second Cutter
1967 -Publication date of this particular edition
The LCC system uses the beginning letters and first line of numbers to indicate the subject of the book. In this example, PS 3537 = Language and Literature (P) > American literature (PS) > Individual authors (PS 700-3575) > 1900-1960 (PS 3500-3549).
The letters are read alphabetically and the subject numbers are read as whole numbers. Sometimes there is a decimal in this number. In such a case, the decimal portion is read as a decimal.
• How do we read decimals? How are they different from whole numbers?
For example, 212.16 comes before 212.5 because .16 is a smaller decimal number than .50. Similarly, 212.257836 comes before 212.3 because .257836 is a smaller decimal number than .300000.
The next part of the call number is referred to as the Cutter number. These numbers further specify a book's identity and subsequent shelf location by applying unique information about that book (such as author last name, book title, geographic location or some other facet of the content) to a table that generates a kind of alphanumeric code. In our example, we have two Cutter numbers: .T3234 & G8.
Cutter numbers contain letters, which are read alphabetically, and decimal numbers, which are read as decimals. So, for example, .T3234 comes after .S76 but before .T381.
Every book has one Cutter number. Some books require two Cutter numbers. In such a case, both Cutters are read as decimals even though the second Cutter does not actually contain a decimal (in order to distinguish the two).
Cutter numbers are named after Charles Ammi Cutter, who developed the Cutter Expansive Classification scheme in the late 19th century. This original system was later adapted by the Library of Congress. For more information about C. A. Cutter, follow this link: http://www.forbeslibrary.org/cutter/cacutter.shtml.
The last number in the above example, 1967, is the date of publication for this particular edition. The publication date might be used to shelve books in chronological order for the same book that was reprinted several times at different dates.
Sometimes a call number will contain a volume number, labeled v.1, v.2, etc. These are shelved in whole number numerical order within that set of books.
A call number will contain a copy number if there are multiple copies of the same book on the shelf, labeled c.1, c.2, etc. These are shelved in whole number order.
If, for example, a book in a set has no volume number, that book comes before any book within that set that does have a volume number. If, for example, there are two identical books on a shelf and one has a call number without a date and another that does, the book without the date (presumably the original edition) comes before the book that does (a reprint of the same edition).