Library of Congress classification system

The Library of Congress classification system is used to classify nearly all the material cataloged by the Princeton University Library.

Different parts of the LC classification system were adopted at different times. The major adoption of the entire system occurred on Feb. 1, 1976.

Some parts of the LC classification have been modified at various times for use in the Library:

• The H classification was modified in the past but is no longer modified.
  
• The N classification was heavily modified in the past. It is now modified only for the numbers for individual artists and architects cataloged for F, SA, Gest, and AAS.
  
• The M classification was modified in the past. It is now modified only for the numbers for individual composers and musicians.