How Items are Organized @Mason

Last Updated: 3 January, 2022 | Provide Feedback

How Mason Libraries Organizes Materials

The Mason Libraries uses the Library of Congress (LC) Call Number system to organize materials (books, DVDs, CDs) on the same topic together. A call number is a set of letters and numbers that can be used to locate items in a library. Call numbers are like addresses for items in a library; each item has its own unique sequence (no two call numbers are the same)! When you look up a physical item in the library's catalog, you will see the call number listed. Each call number begins with at least one capital letter followed by numbers. Below is an example of what you will find in the online catalog for the comic book Miles Morales; Vol.1:Straight out of Brooklyn.

Library catalog result for item Miles Morales; Vol. 1 with the call number PN6728.S6 A36 2019

You read a call number from left to right, and then in sections. If the first line is the same, then you look at the second line and so forth. Use the table below to learn how to read the call number PN6728.S6 A36 2019.

 Line number Example Call Number Description Reading order
Line 1 PN General subject/class; for this example the item is Literature (General) Read in alphabetical order (PN before PO)
Line 2 6728 Narrow subtopic; for this example the item is a comic book Read as a whole number (6728 before 6729)
Line 3 .S6 Author or title Read the letter alphabetically THEN read the number as a decimal (.S6 before .S61 before .T1)
Line 4* A36 Additional author or further narrowing of topic Read the letter alphabetically THEN read the number as a whole number (A36 before A37 before B1)
Line 5 2019 Publication year Read chronologically (2019 before 2020)

*Not every call number includes this line.

Call number tips:

  • Items about similar topics or by the same author will be shelved near each other, so explore the area to find other items you might also like.
  • Break down the call number in rows to make it easier to read. Use the table as an example.

Locating the item using its call number:

  • Items in the library are located in different rooms or floors based on their call number.
  • Within these rooms, items will be on shelves that are labeled with a range of call numbers.
    • Example: a shelf might say that it includes all call numbers between PN2500.N1 to PN6800.A23
  • On the shelves, individual items will have call number labels on the spine.

The information desk at each library has people who can help you locate items, so please ask for help!
When you search for a book on, make sure to note the call number and location, so you can find it easily. Happy Reading!

Get Help

If you need help locating a call number in the catalog, watch the short Mason Search pt. 1 video.

For other questions or if you need more help try Ask a Librarian or explore the subject guide for your discipline. Use the button below to download a printable version of this tutorial.


Creative Commons License How Items are Organized @Mason by The Teaching & Learning Team is licensed under a Creative Commons Attribution 4.0 International License.