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Locate a Book Using its Call Number: Call Number  

How are the Books & Journals Arranged on the Shelves in the Library?


Books, journals and other items are arranged by call number A-Z, using the Library of Congress Classification System.  It is as an alphanumeric system for shelf arrangement by subject.  The call number is a unique identifier that will help you to locate catalogued items in the library.


Reading a Library of Congress Call Number:

 QA 377 .A83 2000 

QA Read letters in alphabetical order e.g. Q, QA, QB, QC...QH...etc377 Read as a whole number e.g. 1, 2, 3, 45, 100, 101, 1000, 2000, 3400, 3485....A83 Read number as a decimal Read letters in alphabetical order e.g. .A83 before .A9 e.g. .C65 before .65 e.g. C72 before .722000 Year of publication Read in chonological order e.g. 1985, 1991, 1992


 Some call numbers are also followed by:

  • Volume number
  • Copy number (if more than one copy)

Examples Call Number Order 

 Q 2301 .M37
QA 2327 .M3
Alphabetically, Q is before QA    

LB 2327 .Y53
LB 2328 .B37
Read as a whole number, 2327 comes before 2328    

B 56  .C50
B 56  .D50
Alphabetically, C is before D
TB 157 .C34
TB 157 .C55
Read as a decimal, .34 comes before .55    

HA 567 .C554
HA 567 .C63
Read as a decimal, .554 comes before .63    

TP 163 .D5 2003
TP 163 .D5 2013
As the year of publication, 2003 comes before 2013 chronologically    

TP1101 .P513  v.65 2009
TP1101 .P513  v.66 2010  
As volume numbers, volume 65 (published in 2009) comes before volume 66 (published 2010)

Understanding a Library of Congress Call Number:

 QA 377 .A83 2000 

For the call number above ( QA 377 .A83 2000 ), Q identifies the category for Science, and QA identifies the subclass of Mathematics.  The letter in the last portion of the call number, .A83, identifies the author, Asmar, followed by a decimal.  For journals or edited works the letter identifies the title rather than the author.  There may be two series of these numbers, followed by publication year, volume, copy.

Library of Congress Classification System: A-Z