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Finding Books at the University Library

Overview of Call Numbers

The Library has a variety materials and, therefore, needs a variety of classification systems for organizing them. 

Library of Congress: Most of our materials are arranged by subject according to the Library of Congress Classification System.  This alpha-numeric call number system uses almost all the letters of the alphabet. Call numbers begin with letters, i.e., CC 78 .T39 1987.

Dewey Decimal System: Our Juvenile Collection, along with most K-12 schools and public libraries, uses this classification system. It is based on 10 categories, each divided into 10 subcategories. The call numbers begin with numbers and contain few, if any, letters.


SuDoc: The US Government created its own system to classify government publications; it is called the Superintendent of Documents system or SuDoc. Call numbers contain a combination of letters, numbers, decimals and colons.Call numbers begin with letters.

The other tabs on this page explain how each of these systems looks and how to use them to physically find books in the Library.

OneSearch allows you to retrieve lists of items held by this Library regardless of how they are physically arranged on the shelf.

Understanding Call Numbers

Most books of the 1.4 million volumes in this Library are cataloged and organized using the Library of Congress Classification System and are shelved by subject, in call number order.

books on shelf

The call number is the address of the book within the Library. After finding a specific book in OneSearch it is important to copy the entire letter-number combination in order to find the book on the shelf, for the entire number identifies one book only. Be sure to note the floor number and wing location as well as any code reflecting collection areas on the floor such as Reference, Atlases, Curriculum, Juvenile, etc.

In the example above the book with the call number HF 485 .C3 is located on the south wing of the second floor. Notice that you can text the call number to your mobile phone if you don't have paper or pencil handy to write it down.

The first line of the call number is a capital letter or combination of capital letters, e.g. AY,E, HF, or PNZ, representing a broad subject area. The second line of the call number is a number representing a narrower aspect of the subject. The third section is a combination of letters and numbers which usually represent the author's last name. There may be a fourth section to the call number and an additional section representing volume numbers or publication year.

To locate the book represented by the call number above, first find the circulating books on 2 SOUTH, then find the H section. Within the H's you'll find them arranged HA, HB HC, HD etc. Find the HF's. Within the HF section find the HF 485 books treating the number as a whole number. Continue to narrow the search for the book by looking at the third line and finding the C section within the HF 485 books.

Careful: The number following the letter on the third line of the call number must be read as a decimal number. This means, for example, that .E536 comes before .E6 on the shelf.

To see what subjects are represented by each letter, click on the tab "Outline of the Library of Congress Classification System" in this research guide.