Reading Call Numbers and Finding a Book on the Shelf

All library books have call numbers.  Call numbers are often described as the "addresses" of where books live within library shelving.  Most people are familiar with the Dewey Decimal Classification System (that is, call number system) from their high school library or often from their local public library.  However, many academic and research libraries use a different classification system called the "Library of Congress" system.  The biggest difference you will notice is the use of letters for subject categories instead of numbers.  Hopefully the following explanation will help you find materials as you adjust to the new system. 

LC call numbers begin with letters of the alphabet.  Each letter stands for a broad subject area. (See below for an outline of these broad areas.)  All letters and numbers that follow the first letter help narrow down that subject area into smaller sections.  No two books will ever have exactly the same call number.

Call numbers can be written either horizontally or vertically.  In our library, call numbers appear horizontally in the online catalog, but they are written out vertically on the label that's put on the spine or the front of the book. No matter how the numbers are arranged they are read the same way.  

This is an example of what a LC call number looks like in the online catalog:

HQ536 .W6215 2001

And here is how the same number is written on the book label:

HQ
536
.W6215
2001

Here is how you read the number:

• Line one is read alphabetically. Single letters are filed before double letters.
        Example: H comes before HQ
   

• Line two is read in straight numerical order; numbers range from 1 to 9999 and are shelved accordingly. KT 100 comes before KT 350, which comes before KT 981.
   

• Line three can be often confusing. Books are arranged first by the letter in line three, then by the numbers. However, the number is a DECIMAL number. (There is usually a decimal point before the letter on that line, but even if the label does not show the point, line three is still treated as a decimal number.) It's frequently a code for the author's name.
  Examples:  .B25 comes before .H18, and .K79 comes before .K8.
   

• Line four can be one of two things:

• In the example above, it's the publication year, and materials are shelved by date: 1985 is shelved before 2004. 

• You may find call numbers where the fourth line looks similar to the third one, although without a decimal point: H23 or D58 or P77. This is shelved as a decimal number, even though there is no decimal point showing. 
  Examples: 1999 comes before 2004, but S16 comes before S2.

• If there is a fifth line, it's usually the publication year, and materials are shelved in date order.

Tip:    When reading or shelving decimal numbers remember the rule:
             “nothing comes before something” 

More practice on reading call numbers is available.

Library of Congress Classification System

Here is an outline of the LC classification table.  When you decide on a degree (nursing, vet tech, commercial education, English lit, whatever) you might want to spend a little time learning the call numbers for your area of studies.

This is not comprehensive – for a complete guide, go to the Library of Congress Classification Online website.

• A - GENERAL WORKS

• B - PHILOSOPHY. PSYCHOLOGY. RELIGION

  • B through BD and BH through BJ -- Philosophy

  • BF -- Psychology

  • BL -- BX Religion

• C - AUXILIARY SCIENCES OF HISTORY

  • CC -- Archaeology

  • CT -- General Biographies (specific biographies are under the subject for which that person is famous)

• D - HISTORY (GENERAL) AND HISTORY OF EUROPE

  • DA Great Britain

  • DC France

  • DD Germany

  • DG Italy

  • DK Russia. Soviet Union. Former Soviet Republics - Poland

  • DP Spain - Portugal

  • DS Asia

  • DT Africa

• E and F - HISTORY: AMERICA

  • E151-889 History of the United States

  • F1-975 United States local history

  • F431-445 History of Tennessee

  • F1226 History of Mexico

• G - GEOGRAPHY. ANTHROPOLOGY. RECREATION

  • GE Environmental Sciences

  • GN Anthropology

  • GV Recreation. Leisure. Sports

• H - SOCIAL SCIENCES

  • HA Statistics

  • HB through HJ - Economics, commerce, and finance

  • HM through HV Sociology (General)

  • HN Social history and conditions. Social problems.

  • HQ The family Marriage. Women

  • HT Communities. Classes. Races

  • HV Social pathology. Social and public welfare. Criminology

• J - POLITICAL SCIENCE

  • JK Political institutions and public administration - United States

  • JS Local government. Municipal government

  • JZ International relations

• K - LAW

  • KF Law of United States

  • KFT Law of Tennessee

• L - EDUCATION

  • LA History of education

  • LB Theory and practice of education

  • LD Education -Individual institutions - United States

• M - MUSIC AND MATERIALS ABOUT MUSIC

  • M1495-5000 Vocal music

  • M5-1490 Instrumental music

  • ML Literature on music

• N - FINE ARTS

  • NA Architecture

  • NC Drawing. Design. Illustration

  • NB Sculpture

  • ND Painting

• P - LANGUAGE AND LITERATURE

  • PN Literature (General)

  • PR English literature

  • PS American literature

• Q - SCIENCE

  • QA Mathematics

  • QB Astronomy

  • QC Physics

  • QD Chemistry

  • QH Biology

  • QK Botany

  • QL Zoology

  • QM Human anatomy

  • QP Physiology

  • QR Microbiology

• R - MEDICINE

  • RC Internal medicine

  • RG Gynecology and obstetrics

  • RJ Pediatrics

  • RT Nursing

  • RS Pharmacy

• S - AGRICULTURE

  • SB Plant culture

  • SD Forestry

  • SF Animal culture

• T - TECHNOLOGY

  • TD Environmental technology.

  • TK Electrical engineering. Electronics. Nuclear engineering

  • TL Motor vehicles. Aeronautics. Astronautics

  • TR Photography

  • TS Manufactures

  • TT Handicrafts. Arts and crafts

  • TX Home Economics

• U - MILITARY SCIENCE

• V - NAVAL SCIENCE

• Z - BIBLIOGRAPHY. LIBRARY SCIENCE. INFORMATION RESOURCES (GENERAL)