Understanding Call Numbers
Every item in the library has a unique call number. The call number is a combination of letters and numbers which may have three to five lines. Call numbers tell you where in the library to find an item, just like you use a street address to find a house. MSU Library uses three different call number systems.
Library of Congress (LC) Classification
The Library of Congress Classification (LCC) is a classification system that was first developed in the late nineteenth and early twentieth centuries to organize and arrange the book collections of the Library of Congress. Proposals for additions and changes are reviewed regularly at staff meetings in the Policy and Standards Division (PSD) and an approved list is published. LC call numbers are based on subjects.
Dewey Decimal Classification
This is a system for organizing the contents of a library based on the division of all knowledge into 10 groups. Each group is assigned 100 numbers and is subdivided into decimals. Some older documents in the library may use the Dewey Decimal system. Dewey call numbers are grouped together by subject.
U.S. Government publications are arranged by the Superintendent of Documents (Sudoc) classification number. Publications are grouped together by issuing agency.