The Cerritos College Library uses Library of Congress Call Numbers to shelve books. This system uses a combination of letters and numbers to arrange materials on library shelves by subject. This system is in use at the Library of Congress and at many academic and research libraries in the United States.
The letters range from A through Z, and can be one or two letter combinations. The combinations of letters and numbers that are assigned to books are called CALL NUMBERS. The first letter of the CALL NUMBER designates a broad subject range. The second letter denotes a refinement or division of the subject indicated by the first letter.The leters and numbers that follow refine the topic even more. Every book has a unique call number but call numbers can be very similar if two books are about the same topic.
For example:
P Language and Literature
PS American Literature
Q Science
QH Biology
R Medicine
RT Nursing
T Technology
TK Electrical Engineering
Since the Library of Congress Classification system arranges materials by subjects, call numbers can tell you a lot about a particular book.
Example:
Library of Congress call numbers are usually four or five lines. On the shelves, books are arranged alphabetically by the letter or letters on the first line and then numerically and alphabetically line by line. The first line places the book in its subject area on the shelves.
Think of using the CALL NUMBER to locate a book in the same fashion that you use an address to locate a house on a street. Like an address, a call number gives you the information from the very general (city and state) to the very specific (apartment number). The following example show how call numbers are arranged, going from the very general (Library of Congress classification letters) to the very specific (using numbers and decimals).
