The Library of Congress Classification System (LoC) is used in Isothermal Community College Library to organize and index the library's book collections. The LoC System organizes items by subject rather than by genre, as is the commonly used system in public libraries.
Each book is assigned a call number which is typed on a label and attached to the book's spine (see illustration below), designating its location on the shelf at the same time it indicates the subject area about which the book is written.
Books shelved using the LoC system are first divided into large sections designated by letters of the alphabet: a section of A's, a section of B's, C’s, D’s, etc., continuing through the alphabet.
Each of these sections is further broken down by adding a second letter to the main section letter; for instance, CA, CB, CC and so forth; a third letter is added in a few cases. Added after the main letter designations, alternating letters and numbers break down subject areas into greater and greater detail.
A simple breakdown of the LoC system is available online* and posted on the end of the shelving in the Reference Collection, showing main letter combinations and the subjects they represent.
* Source: “LC Classification Outline, 7th Edition: Contents.” n.d. Cataloger’s Reference Shelf. The Library Corporation. [“based on LC Classification Outline, Seventh Edition, 2003, Cataloging Policy and Support Office, Library of Congress; Cataloging Distribution Service, US Library of Congress, Washington, D.C.”] Web. 6 Oct. 2015.