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Understanding Call Numbers

The Library of Congress Classification System

The Lawrence W. Tyree Library arranges its books by the Library of Congress Classification System (LC). This is the system used by most academic libraries (including the University of Florida) and works on a system of letters denoting broad subjects, further divided by numbers as the subject gets more specific.

Below is a quick guide to the LC subject areas. To see how the areas are set up, click on any of the topics.

What do the call numbers mean?
How do you find LC call numbers on the shelf?

+ A - General Works

AC Collections, Series, Collected works.
AE Encyclopedias (General).
AG Dictionaries and other general reference works.
AI Indexes (General)
AM Museums. Collectors and collecting.
AN Newspapers.
AP Periodicals.
AS Academies and learned societies (General).
AY Yearbooks. Almanacs. Directories.
AZ History of scholarship and learning. The Humanities.

+ B - Philosophy, Psychology, Religion

B Philosophy (General).
BC Logic.
BD Speculative philosophy.
BF Psychology, Parapsychology, Occult sciences.
BH Aesthetics.
BJ Ethics. Social usages. Etiquette.
BL Religion.
BM Judaism.
BP Islam, Bahai, Theosophy.
BQ Buddhism.
BR Christianity.
BS Bible.
BT Doctrinal theology.
BV Practical theology.
BX Christian denominations.

+ C - Auxiliary Sciences of History

CB History of civilization.
CC Archeology.
CD Archives.
CR Heraldry.
CS Genealogy.
CT Biography.

+ D - World History: General and Outside the Americas

D World History, including World Wars.
DA Great Britain.
DB Austria.
DC France.
DD - DZ Other European countries.
DS Asia.
DT Africa.

+ E - History: United States

E 11 - 143 America, Pre Revolutionary War.
E 184 - 185 Population (Including African American history).
E 201 -298 Revolutionary War.
E 456 - 655 Civil War.
E 780 World War I.
E 806 - 812 Franklin Roosevelt's administration (Including WW II).
E 855- 861 Watergate.

+ F - History: United States (Local) and the Americas

F 1 - 950 U.S. regions and states.
F 306 - 320 Florida history.
F 975 Central America.
F 1001 - 1139 Canada.
F 1201 - 3799 Latin America.

+ G - Geography, Anthropology, Recreation

G Geography (General).
GB Physical geography.
GC Oceanography.
GN Anthropology.
GR Folklore.
GV  Recreation.

+ H - Social Sciences

HA Statistics.
HB - HJ Economics.
HF 5381 - 5386 Vocational guidance.  Career development.
HM Sociology.
HQ Family, Marriage, Women.
HS Societies: secret, benevolent, etc.
HT Communities.  Classes.  Races.
HV Social Pathology, Criminology.
HX Socialism.  Communism.  Anarchism.

+ J - Political Science

JA - JC Political science.
JF - JQ Constitutional history and public administration.
JS Local government.
JX International law.

+ K - Law

K Law in general.
KF Federal law.
KFF Florida law.

+ L - Education

LA History of education.
LB Theory and practice of education.
LD  Individual institutions - United States.

+ M - Music

M Scores.
ML Literature of Music.
MT Musical Instruction.

+ N - Fine Arts

NA Architecture.
NB Sculpture.
NC Graphic arts.
ND Painting.
NK Decorative arts.

+ P - Language and Literature

PA Classical languages and literature.
PC Romance languages.
PD - PF Germanic languages, Including English (PE).
PG Slavic languages.
PJ - PL Oriental languages and literature.
PN Literature, drama, radio, television, film.
PQ Romance literatures.
PR English literature.
PS American literature.
PT Germanic literature.
PZ Juvenile literature.

+ Q - Science

QA Mathematics.
QA 75 - 76 Computer hardware & software.
QB Astronomy.
QC Physics.
QD Chemistry.
QE Geology.
QH Natural history.
QK Botany.
QL Zoology.
QM Human anatomy.
QP Physiology.
QR Bacteriology.

+ R - Medicine

RB Pathology.
RC  Internal medicine.
RG Gynecology.
RJ Pediatrics.
RK Dentistry.
RM Pharmacology.
RT Nursing.

+ S - Agriculture

SB Plant culture and horticulture.
SD Forestry.
SF Animal culture.
SH Fish culture and fisheries.
SK Hunting sports.

+ T - Technology

TA General engineering.
TC Hydraulic engineering.
TH Building construction.
TJ Mechanical engineering.
TK Electrical engineering and computer engineering.
TL Motor vehicles, aeronautics, astronautics.
TN Mining engineering.
TR Photography.
TS Manufactures.

U - Military Science

V - Naval Science

Z - Library Science

This list is not inclusive, but merely designed to reflect the subjects held at the Santa Fe College Library. For a full list of subjects covered by the LC system please view the Library of Congress Classification Outline online.

Understanding Call Numbers 


To be able to efficiently read Library of Congress (LC) call numbers is quite a skill. This tutorial was created to help library users uncover the mysteries of call number reading. Let's start with a sample call number: 

RJ245 .P426 2000 

Call numbers can begin with one, two, or three letters.

  • The first letter of a call number represents one of the 21 major divisions of the LC System. In the example, the subject "R" is Medicine.  
  • The second letter "J" represents a subdivision of medicine, Pediatrics. All books in the RJ's are primarily about pediatrics.  
    • Books in categories E, United States History, and F, Local U.S. History and American History, do not have a second letter (exception: in Canada, FC is used for Canadian history).  
    • Books about Law, K's, can have three letters, such as KFF, Law of Florida. Some areas of history (D) also have three-letter call numbers. 
    • Most other subject areas will have call numbers beginning with one or two letters. 
  • For most of the subject areas, the single letter represents books of a general nature for that subject area (i.e. Q - General Science or D - General World History). 

Numbers after letters.

  • The first set of numbers in a call number help to define a book's subject.  
  • "245" in the example teaches us more about the book's subject. The range RJ 245-247 are books about nursing of children and pediatric nursing. 

Cutter Number

  • The cutter number is a coded representation of the author or organization's name or the title of the work (also known as the "Main Entry" in library-lingo). This is usually a decimal point and a letter followed by a group of numbers.
  • In our above example, RJ 245 .P426 2000, the P426 represents the title of the work Pediatric Nursing.
  • Some books have two Cutters, the first one is usually a further breakdown of the subject matter.
    • For example, RT 120 .F34 C37 1989 is a book located in the medical section, R's.
      • RT is about Nursing.
      • The "120" indicates specialties in nursing.
      • ".F34" tells us that this is about family nursing - case studies.
      • "C37" represents the title of the book.
      • The book is Case studies in the nursing of children and families : hospital, community, and home care

Years, Supplements, Copies etc.

  • The last lines on a call number often represent copyright information, volume information, copy information etc. 
    • For example in the last line of our call number RJ 245 .P426 2000, we see that the book was published in 2000.  
    • If this was a multi-volume set, the call number would end with v. 1, v. 2, etc. 

Shelving and Locating

Items are shelved by call numbers - in both alphabetical and numerical order. The letters at the beginning of the call number are alphabetical. The numbers immediately following are in basic numerical order, i.e. 5 then 6, 50 is after 49 and before 51, and 100 is after 99. Thus,



The cutter numbers (A3, A31, Z4, C3, and A2 in the above example) are sorted first by the letter and then by the number as a decimal. The main thing to remember with this number is that the dot really does work as a decimal place, so that .A1002 comes before .A9. Therefore,


Dates, volume and issue numbers, copy numbers, and other annotations are like an additional cutter number but are shelved by basic alphabetization (numbers alone come before letters):

c. 1
c. 2