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Library Skills Instruction: Call Numbers

Purpose of the Call Number

Books in the library are assigned call numbers.  They consist of letters and numbers.  The call numbers allow the researcher to find the shelving location of the book within the library.  The books are shelved alphanumerically.

Library of Congress Classification

The Library of Congress Classification system is created by the largest library in the United States.  Webster's Ninth New Collegiate Dictionary has been assigned the following call number:  




  • Each call number begins with one or two letters, usually.
    • PE 
  • Next, are 1-4 numbers
    • 1628
  • Followed by a decimal point and 1 letter and number(s)
    • .W5638 

The first 2 lines, PE1628,  represent the topic of the book, Modern English language minor abridged dictionaries 

The third line, .W5638, represents the author's last name, Webster 

Where to Find the Resources

with Call Numbers A-HF
   Second Floor

with Call Numbers HG-Z
   Third Floor

Current (1-2 Years Old) Magazines and Journals
   First Floor

   First Floor

Older Magazines and Journals     Second Floor

Reference Books
   First Floor--Ready Reference
   Second Floor--Reference

To Find Books

The books in the library have call numbers assigned to them.  They are shelved according to the call number.  

  • To get the call number:
    • Do a search in the IUCAT (online catalog)
    • If the library owns the book, bibliographic information will appear on the screen; click the book's title
    • Scroll down to "Holdings" and find Northwest under "Library"
    • Below "Library" is the section, "Call Number;" write the call number
    • Notice where the book is within the library under the section, "Location"
  • The first letter on each book is grouped alphabetically
    • P, PA, PB, PC, PD, PE, PF...PZ
    • Q, QA, QB, QC, QD, QE, QF...QZ
  • The first numbers are grouped numerically after the respective letter,
    • P1, P2, P3, .., P5...P5029-P999, PA1, PA2...PB1-PB999, PC,,.PE1-PE1628‚Äč.
  • The third line begins with a decimal point and a letter, followed by a number
    • .A3, .B2, .C62.....W56, .W5638, .W57.

Therefore, the call numbers below should be shelved, accordingly:

PE               PE                PE

1628            1628             1628

.W5              .W5638         .W9


According to the IUCAT, editions of this book are shelved in "Reference" and in the "Stacks."  Consult the box, "Where to Find the Resources" to find the respective sections.