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Using Call Numbers to find Books


The Langara College Library uses Library of Congress (or LC) Call Numbers to organize the print collection. The call number is usually found on the spine of the book and represents what the book is about. A call number acts like a book's address on the shelf, and ensures books on similar subjects are shelved near one another. Understanding how to read a call number and what each part means will help you find books on the shelves more quickly. 

Parts of a Call Number

The first two lines indicate the subject of the book.

  • The letters are a wide subject area, and the numbers that follow are a specific subject within the wider area. 
  • Example: in this case Q is Science, QB is Astronomy, and 460 is Astrophysics. 

The next line is called the cutter number, it indicates the author or topic to ensure that similar works will be placed together on a shelf, in alphabetical order within their subject area.

  • Some books have a second cutter number to define subject matter more clearly.
  • Sometimes the cutter number is preceded by a decimal point.

Cutter numbers are followed by another line of information to help distinguish one similar item from another, often the year of publication, volume, or copy number.