Understanding Call Numbers

Folke Bernadotte Memorial Library

Our library, like many academic libraries, uses the Library of Congress Classification System to organize library materials. When books are cataloged, they are assigned a call number. These call numbers are like addresses, telling you where to find the book in the library. Understanding call numbers can be tricky at first, but with patience and practice--plus a look at this guide--you will soon be an old hand at reading call numbers.

Call numbers use a combination of letters and numbers to arranged books according to subject. The Library of Congress Classification System divides areas of knowledge into 21 main classes, assigning letters to each class. For example, the letter K is assigned to Law, so books about Law will be found in the K section of the library. The 21 main classes are further subdivided into specific subject areas, which have also been assigned alpha or numeric codes. Codes indicating information about the author and publication year are added to the subject code and voila! you have a call number.

You don't need to worry about how catalogers come up with call numbers. All you need to remember is that books are shelved according to subject and that call numbers tell you where to find the exact book on the shelf. To read more about how the Library of Congress system works, click here.

Reading Call Numbers

Let's take a look at how call numbers are composed. Read the call number line by line, top to bottom. This is how the call number will appear on the spine of the book. Call numbers are also found in the MnPALS Plus library catalog. Note that in the catalog, the call number will usually be displayed as one line: BR 526 .G55 1993. The call number is the same, whether written in four lines on the side of a book or in one line in the catalog.





  • Read the first line in alphabetical order. (BR comes before BS on the shelf.)
  • Read the second line as a whole number. (BR 526 is located after BR?43.)
  • Read the third line alphabetically, then by decimal number. (.G55 comes before .L63;
    .G55 comes after .G123--remember that as a decimal, .55 is larger than .123)
  • Read the fourth line as a whole number; it is the publication year of the item.

Identifying the Collection

Before go to the shelves to look for your book, first determine in which part of the collection the book is located. If you have done a catalog search in MnPALS Plus, check out the Location line. Most of our books are located in the General Collection, meaning they can be found on the second and third floors. Call numbers beginning with A - PQ are found on the third (top) floor; call numbers beginning with PR - Z are found on the second (main) floor. Click here for a map of the library.

Other collections use the same call number system, but are located in different parts of the library. The location column will tell you in which collection the book is found. Collections include:

  • Reference (located on the second loor)
  • General Collection (A - PQ located on third floor, PR - Z located on second floor)
  • Oversize (located on the third floor, southwest corner)
  • Hasselquist (located in the room behind the reference desk on the second floor)
  • Browsing (located near the newspapers on the second floor)
  • Audio Visual (located on the first (bottom) floor)
  • Children's Literature (located on the first (bottom) floor, south end)

*Note: Government Documents, which can be searched via MnPALS Plus, use a different call number system. These items are located on the bottom floor. For more information on locating Government Documents, click here or visit the reference desk.

Finding Books on the Shelf

Once you have determined in which collection your item is located, start by going to the letter of the section that corresponds to the beginning of the call number. For example, for the call number BR 526 .G55 1993, go to the B section. (Remember, call numbers beginning with A - PQ are located on the third floor; letters are clearly marked on the top of bookshelves.) Once you are in the B section, look at the tags on the sides of the shelves. These tags give the range of call numbers found on each side of the shelves. Bowse the tags until you find the BR section.

Next, look in the BR section for the whole number 526. The tags on the sides of the shelves will direct you to the correct row. For example, if the tag on the side of the shelf looks like this:





v. 1






the book will be located somewhere in this row of shelves, because BR 526 falls in between BR 331 and BR 1720. Find the BR 526 section and use the rest of the call number to locate the book.


Remember that books are shelved according to subject, which means that you will find similar books on your research topic near each other. When you find a book that fits your research topic, take a look at the other books nearby. You might end up with a few more sources!

For more information on the serendipity of browsing, click here.

Last updated September 4, 2012