Understanding Call Numbers

A call number is like an address for a book or other item in the library. It tells you where the item is located and groups it with materials on similar subjects.

At the Michael Schwartz Library, most items are assigned call numbers using the Library of Congress Classification system, which uses letters and numbers to arrange materials by subject.

Example of a call number on a book and in Discovery

What does a call number mean?

In this example, the book is Nuclear and Particle Physics by W.S.C. Williams, published in 1991.

  • QC represents the general subject area, in this case Physics.
  • 776 narrows the subject to Nuclear and Particle Physics.
  • .W55 is a cutter number that represents the author’s last name, Williams.
  • 1991 is the publication date in this example.

Some call numbers have more or fewer parts. They may include a volume number, edition information, or other details instead of a publication date.

How do you read it?

Close-up of a call number label on a book spine

Read a call number line by line:

  • QC is read alphabetically, so it comes after QB and before QD.
  • 776 is read as a whole number, so it comes after QC 775 and before QC 777.
  • .W55 is read as a letter plus a decimal, so it comes after .W5 or .W54 and before .W56 or .W6.
  • 1991 is read chronologically, so it comes after 1990 and before 1992.

Finding it on the shelf

Once you find a book in Discovery, note both the call number and the location. The location tells you which floor or collection to go to, and the call number tells you where the book belongs on the shelf.

  • Go to the floor listed in the Discovery record.
  • Find the shelving range that includes the first part of the call number, such as QC 776.
  • Use the signs at the ends of the shelves to narrow to the correct range.
  • Then look for the next part of the call number, such as .W55, in alphabetical and decimal order.

Because books are shelved by subject, you will often find related books nearby once you locate the one you want.

Books on a shelf arranged by call number

Need help finding a book?

Use the library’s Book Locations by Call Number page and the library floor plans to locate materials in the building.

You can also try Kent State University’s Shelf-Reading Tutorial for extra practice.

If you need assistance, contact the Research Help Desk at (216) 687-5300.