Library of Congress call numbers are used to organize books in a library. They consist of three main parts: the subject, a subdivided subject category, and the author's last name. For example, the call number HM 133 .B483 1993 indicates a book on sociology (HM), specifically group relations training (133), written by author Harvey J. Bertcher (.B483) and published in 1993. Call numbers are arranged alphabetically and numerically, with decimal places used to further subdivide subjects by specificity.

1. Books
Library of Congress Call
Numbers

2. LCCN – Library of Congress Call Numbers
Book Title: Group participation : techniques for
leaders and members, by Harvey J. Bertcher
HM
133
.B483
1993
• Like a code or an address
• 3 Main parts
– Main subject (HM – Sociology)
– Subdivided subject (133 – Group
relations training)
– Author (.B483 – code for author’s
last name)
• Can also include date of
publication (1993)

3. LCCN – Library of Congress Call
Numbers
• First Line: Arrangement is
alphabetical: D, DA, DB,
etc.

4. LCCN – Library of Congress Call
Numbers
• Second Line: the
arrangement is by whole
number: DB1, DB2, DB3…
DB22…DB100

5. LCCN – Library of Congress Call
Numbers
• Third Line: the number is
read as a decimal rather
than a whole number:
DB
22
.A5
.A56
.A562
.A6

6. LCCN – Library of Congress Call
Numbers
• Third Line: the number is
read as a decimal rather
than a whole number:
DB
22
.A5
.A56
.A562
.A6