Organizing all the world's knowledge...

Organizing information is precisely what librarians do. Information on any topic you think of can be found by using in a library classification system.

Since 1898 the Library of Congress (LC) in Washington DC has been organizing the world's knowledge, first for the U.S. Congress and then for all the libraries in the United States.  The lettering and numbering system the Library of Congress uses to organize its information is called the Library of Congress System.  This system includes LC Subject Headings to help you find books on a particular topic and LC Classification to help you find the books you want on the shelf.

For more information about The Library of Congress go to:  http://www.lcweb.loc.gov/

Library of Congress Subject Headings

Library of Congress Subject Headings (LCSH) should be considered a grand index to the Library of Congress Classification System. Just as a book on any particular topic (for instance, rights of animals) will be located on the bookshelves with a classification number (e.g., HV 4711), so will that book have unique subject headings assigned to it (e.g., Animal Rights). By using this uniform approach, all books about a particular topic will be shelved near each other, and can be identified and located by looking up the correct subject terms in the library's catalog.

The updating of subject headings is a continuous process and each year more than 5,000 headings are added. Currently there are more than 200,000 subject headings!

Large subject topics are divided with specific subdivisions. A large topic like AIDS is divided by using many subdivisions that allow you to zero in on government policy, if that is your focus. Topics that are related to the one you searched for are listed as related terms (RT). Small topics have the broader division listed. By using the broader terms (BT) you can find more general information. Using the narrower terms (NT) can narrow topics that seem a little too big.

Example of an LC Subject Heading:

Library of Congress Classification System

The Library of Congress Classification System is used to organize books on the shelves in many college and university libraries throughout the United States and the world. The LC SYSTEM organizes material in libraries according to twenty-one branches of knowledge called classes.  The system uses letters to represent the twenty-one broad branches of knowledge.  The letters I, O, W, X AND Y are not used.

The twenty-one branches are:

A – GENERAL WORKS

B – PHILOSOPHY, PSYCHOLOGY, RELIGION

C – AUXILIARY SCIENCES OF HISTORY

D – HISTORY: GENERAL & OUTSIDE THE AMERICAS

E – HISTORY: UNITED STATES

F – HISTORY: UNITED STATES LOCAL & AMERICAS

G – GEOGRAPHY, ANTHROPOLOGY, RECREATION

H – SOCIAL SCIENCE

J – POLITICAL SCIENCE

K – LAW

L – EDUCATION

M – MUSIC

N – ART

P – LANGUAGE & LITERATURE

Q – SCIENCE

R – MEDICINE

S – AGRICULTURE

T – TECHNOLOGY

U – MILITARY SCIENCE

V – NAVAL SCIENCE

Z – LIBRARY SCIENCE & INFORMATION RESOURCES

These twenty-one broad subject areas are further divided into more specific subject areas by adding one or two additional letters as well as some numbers.  
 

The following links will take you to pages where you will find outlines of the Library of Congress Classification System.

Library of Congress Classification - By Subject

Library of Congress Classification Schedule - Detailed

Library of Congress Call Numbers

The Cerritos College Library uses the 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. For example:

P     Language and Literature

PS   American Literature

Q     Science

QH   Biology

R      Medicine

RT    Nursing

T     Technology

TK    Electrical Engineering

What Does the Call Number Mean?

 The Library of Congress Classification arranges materials by subjects.

• The first section of the call number represents the subject of the book.
• The letter-and-decimal section of the call number often represents the author's last name.
• The last section of a call number is often the date of publication.

Example:

 

How Do You Read A Call Number?

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).

 

How Do You Locate Books on the Shelf?

Call numbers are arranged line by line, just as they are read, starting with the letter or letters in alphabetical order:

 

Cerritos College Library Location Designations

Location designations may appear above the call number and indicate that the book is shelved in a special location in the library. Some of the location designations used in the Cerritos College Library are:

REF = Reference Collection

REF DESK = Reference Desk

SC = Short Story Collection

CHILDLIT = Children's Literature Collection

RESERVE ITEM AT CIRCULATION = Circulation Desk, limited loan period