Library of Congress Call Numbers
Most of Manhattanville's books are shelved according to the Library of Congress Classification System. This Classification System uses 21 letters of the alphabet to describe its subject classification.
Subject Headings
If you are going to search for a book or other source by subject, you must understand that the Library of Congress issues the standardized terminology (controlled vocabulary) for library catalogs (printed and online) which allows for consistency from one library to another.
The Library of Congress Subject Headings, a five-volume manual, contains the controlled vocabulary for libraries and can be used to help locate appropriate subject headings on your topic. These "big red books" listing the subject headings are your access tool.
An access tool is an information source that leads you to information. The access tool does not always provide the actual material that you need, but it will sometimes provide you with the information that you need to find that material.
Some access tools may list their controlled vocabulary terms in a thesaurus. You may have used a thesaurus in the past to find synonyms when writing a paper, but in the case of an access tool, the thesaurus is a list of descriptors/subject headings.
The access tool will usually include a main term, a broader term, a narrower term, and a see also term. The thesaurus will also show terms that should not be used to search (these are terms that the indexer did not choose to use as appropriate descriptors for that source).
How to Read a Call Number
A call number is a series of letters and numbers assigned to each publication according to its main subject. The Library of Congress Classification System allows the assignment of only one subject number to each item in the system. This means that although an item may correspond to many different subjects, it will have only one call number.
Once a call number has been assigned, the item is then placed on the shelf with other items that deal with the same subject. When you find the call number for a subject, you may go to that area in reference or the book stacks and browse the shelves for resources on your topic. The call number functions as the "address" for books and subject areas on the library shelves.
Example: Library of Congress Subject Headings and Abbreviations:
| May Subd Geog | May subdivide geographically |
| BT | Broader topic
More general headings. If there are too few books under the main heading, try a broader heading. |
| NT | Narrower topic
More specific topics. If there are too many books under the main heading, consider using a narrower heading. |
| RT | Related topic
Associated headings that fall outside of the main term's hierarchy. |
| SA | See also
Headings that cover similar subjects. |
| UF | Used for
These are unauthorized headings. Do not use these headings. |
| USE | Refers to the appropriate heading |