Rensselaer Libraries

How Our Books Are Organized

Posted: Oct 20, 2009

How Our Books Are Organized

Almost all materials (i.e. books, journals, audio cassettes, videotapes, and microfilm) housed in a library are assigned call numbers.

  • Call numbers identify an item's subject and location in a library.
  • Call numbers are assigned to items based on a classification scheme. Library materials on similar topics will have similar call numbers and will be shelved together.
  • There are three major classification systems used by most libraries in the United States--Library of Congress Classification System (LC), Dewey Decimal Classification System (DDC), and the Superintendent of Document System (SuDocs).
  • Rensselaer Research Libraries use all three of these systems.


The Library of Congress (LC) classification system is used to catalog our books . This system is used to assign call numbers to and shelve books in the Reference Area and Book Stacks. The LC system divides materials into 21 different subject areas. An LC call number consists of one or two (or rarely three) letters followed by a number. The initial letter or letters indicates the general subject of the book.



QR358 .M34 2001 Example of a book Call Number



Our web page Location/Call Number Guide will direct you to library materials and provide floor plans to locate collections. Also there is a floor plan on each floor directly opposite the stairwells.

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