Reference and Instructional Services Department

How to Read a Call Number

The University of Delaware Library uses the Library of Congress classification system to organize most materials. Each book (or bound volume of a periodical) is assigned a call number - a unique number that specifically identifies one copy of one book. A book is shelved according to its call number. Therefore, the call number also serves as a book's address or location in the building. The Library of Congress classification system groups books on the same subject together on the shelves.

A call number is always read line-by-line, from top to bottom. Library of Congress call numbers always start with letters - typically one or two letters, sometimes three.


Above is an example of call numbers in order, as you might see them on the spines of books on the shelves.




The first letter of the call number indicates the floor where thoses call numbers are shelved. Special locations may be listed before the call number.


Call number floor locations:   Examples of special locations:
A-H 3rd Floor
J-K LL (Lower Level)
L-N 3rd Floor
P-Q 2nd Floor
R-Z LL (Lower Level)
Reference Reference room, 1st Floor
Library Annex Off-site; request items from the Annex using the Library Annex Request Form


More Information

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