The Library of Congress (LC) Classification System is subject-based, classifying and arranging items by the subject matter involved. The Hampshire College library uses LC call numbers for most of its collection.

• The LC system is broken into 21 primary classes, or general subject areas, represented by letters.
• By breaking items into 21 subject areas the LC System allows libraries to classify and arrange larger collections by the main subject matter of the text.
  
  

  A - General Works B - Philosophy, Psychology, Religion C - Auxiliary sciences of history D - World History E-F - History of the Americas G - Geography, Anthropology, Recreation H - Social Sciences J - Political Science K - Law L - Education

  M - Music and Books on Music N - Fine Arts P - Language and Literature Q - Science R - Medicine S - Agriculture T - Technology U - Military Science V - Naval Science Z - Bibliography. Library Science

• The LC system further breaks these subjects into subclasses by the addition of one or two letters followed by numbers up to four digits plus several decimal places in length. For example:
  
  
  • LC call numbers beginning with Q deal with Science
  • LC call numbers beginning with QL deal with Zoology
  • LC call numbers beginning with QL 700 deal with Mammals
  • LC call numbers beginning with QL737 deal with Gorilla Behavior
    The LC call number for Gorillas in the mist, by Dian Fossey is:
    QL737 .P96 F67 1983
• For a list of the major classes and subclasses of the LC classification system, click here.
• The second part of an LC call number includes a code representing the author and the particular item. This part of the call number begins with a letter followed by numbers, and then sometimes another letter followed by numbers.
  For example, Gorillas in the Mist:
  QL737 .P96 F67 1983
• Frequently an LC call number will include a final part that represents the year that the item, or particular issue of an item, was published.
  Again, Gorillas in the Mist:
  QL737 .P96 F67 1983

Reading LC Call Numbers

• Library of Congress call numbers are arranged alphabetically and numerically. Call numbers are read from left to right and from top to bottom. Sometimes call numbers are written out all on one line as you see above, and sometimes they are displayed in a column as below. An LC call number is read the same way whether it is all on one line or in a column.
• Letters in the first part of the call number are in standard alphabetic order from A to Z:
  
  

  H45 .E37 1984

  HA155 .A5 1944

  HB21 .A33 1982

  HC13 .S47 1990

• Numbers in the first part of the call number are in regular numerical order:
  
  

  B53 .D476 1990

  B785 .L44 M67 1991

  B1201 .B44 W64 1997

  B1246 .R66 1986

• Letters in the second part are again A to Z:
  
  

  KF240 .B265 1981

  KF240 .C538 1989

  KF240 .S795 1995

  KF240 .T38 1989

• Numbers in the second part of the call number are in decimal order. It is important to remember that there is a decimal point before this number:
  
  

  L901 .C33

  L901 .C347 1971

  L901 .C37 1976

  L901 .C4 1996

• There may be a third set of letters and numbers. These will also be in alphabetical and decimal number order, even though the decimal point will not be shown.
• The last part of a call number may be a year. This indicates the publication date.

Library of Congress Classification System

This is a very basic outline of the Primary Classes and Subclasses of the LC Classification System. To see a much more detailed classification list at the Library of Congress website, click here.

Primary Class: A | B | C | D | E-F | G | H | J | K | L | M | N | P | Q | R | S | T | U | V | Z |