Understanding Call Numbers: Library of Congress Call Numbers
Library of Congress Classification (LC)
LC call numbers begin with letters.
In the online catalog, typical LC call numbers look like:
HB3505 .E44 1992
On book spines, or labels on other materials, LC call numbers are arranged vertically and would typically look like:
A– General Works
AY– Yearbooks, Almanacs, Directories
BD - Philosophy
C– History-Auxiliary Sciences
D– World History
DB– Eastern Europe
DS—Asia & Middle East
E 1-143 - America
E 151-857—US (General)
F 1-957—US (Local)
F 1001-1140 - Canada
F 1201– Central & South America
GB– Physical Geography
HE—Transportation & Communication
HQ—Family, Marriage, Women
HT– Cities, Communities, Race
HV– Social Service, Welfare, Criminology
Library of Congress Call Numbers
Understanding the Parts of Library of Congress Call Numbers
Library of Congress (LC) call numbers can be a challenge to read when you first start using LC classification. This LibGuide was created to help library users uncover the mysteries of call number reading. Let's start by looking at a book in our collection: Elephants in the Volkswagen : facing the tough questions about our overcrowded country by Lindsey Grant. This books call number is:
HB3505 .E44 1992
Let's break this call number down and learn how to read it.
Call numbers can begin with one, two, or three letters.
- The first letter of a call number represents one of the 21 major divisions (bold text in the boxes to the sides) of the LC System. In the example, the subject "H" is Social Science. The added "B" breaks it down to Economics subdivision.
- Most of the subject area divisions have one or two letters. However, there are some that have only one (E-America) or can have up to three letters (K-Law).
- 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 and are read as a whole number. This number can be one digit, several digits, and even have a decimal. In the example, "3505" tells us this book is about general United States demography or information about the population.
- Books with call numbers that start with HB3501-3697 are about the demographics of different regions or countries.
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).
- Charles Ammi Cutter first developed cutter numbers using a two-number table.
- A three-number table was developed in 1969.
In our above example, HB3505 .E44 1992, the .E44 represents the first three letters of the book title Elephants in the Volkswagen : facing the tough questions about our overcrowded country by Lindsey Grant. Some books have two Cutters, usually a further breakdown of the subject matter.
For example, QA 76.76 H94 M88 is a book located in the Mathematics section of the Q's.
- QA 76 is about Computer Science.
- The ".76" indicates Special Topics in Automation.
- "H94" tells us that this is a book about HTML.
- "M88" represents the last name of the first author listed's last name, Musciano.
- The book is HTML: The Definitive Guide
Dates and Volume Numbers
The last number in the call number is the copyright date, the year the book was published. This can help you quickly find a book if you need one that is more recent. On some books you may see a volume number, with "volume" being abbreivated "Vol." or even just "V."
This covers the basics of a LC Call Number. You can find some other numbers on labels at times, but the majority of books follow this pattern.
Just be sure to ask at any of the desks for assistance if you have questions.
Reading the LC Call Number
To read a LC call number you simply go down the label, reading each line as you go.
Let's break it down using our example above:
You would first look for the "HB" section. All the books whose call numbers start with HB will be together on the shelf.
You then look for the "3505". Remember this is a whole number, three thousand five hundred and five. Some books may have a decimal in this number, breaking the topic down more. All books with HB 3505 will be together on the shelf, with HB 3505 coming before any that may have a decimal after the 3505.
You then move to the next line, ".E44". Any number after the "." here is read as a decimal. You would find the books that have HB 3505 .E and look for .E44. One way to read it is E .44. This decimal is important to remember, ".E6432" would come BEFORE ".E705" which would be BEFORE ".E9".
The last line is the date the book was published, 1992. There can be books that are re-printed so they can have different dates here. So 1990 would come before 1992.
Some call numbers are preceded by a location prefix indicating that the item is shelved in a specific location and may have loan restrictions. For example:
REF - Reference item located on the Reference shelves on the 1st floor, East Wing. These books do not check out.
BANDY and ROBERTS - Reference items with BANDY prefix have been donated by the Bandy Heritage Center and are located in the Bandy Heritage Center collection while the ones with ROBERTS are from the personal collection of Dr. Derrell C. Roberts, former president of the college for whom the library is named. The ROBERTS collection are housed in the library archive. These two collections do not check out.
The books that do not have a location prefix should all check out.
Subject Areas - continued
Library of Congress
JF– Constitutional History
JK– United States
JQ- Asia, Africa, Australia, Oceania
JX—International Relations & Law
LA- History of Education
LB- Theory & Practice
LD- U.S. Institutions
ML - Literature of Music
MT - Musical Instruction
N- Fine Arts
NE- Print Media
P-Language and Literature
PA- Classical Languages
PC- Romance Languages
PE- English Language
PN- General & Comparative Lit.
PR- English Literature
PS- American Literature
PZ- Fiction: Juvenile Literature
QA- Math & Computer Science
QH- Natural History, Biology
QM- Human Anatomy
RA- Public Health
RC- Internal Medicine
TA- Civil Engineering
TD- Environmental Technology
TH- Building Construction
Z-Bibliography & Library Science