LibAnswers

When you already know the call number

To look up a book in the catalog when you already know the call number, go to the Library website and select "Advanced Search."

From there, select "Holding Call Number" from the Search Filters drop-down, enter your call number into the search field, and execute your search.

When you don't already know the call number

First, to find a book (or other physical item) in our collection, you can search our catalog. From the Library website, select "Advanced Search." Next, select the radio button for "Hannon Only" so that your search is limited to our collection. Execute a search for the item you're looking for.

If a physical item in our collection is returned in your search results and the item is on our shelves and available, you'll find a notation beneath the title that says where you'll find the book (on the 3rd floor, for example), followed by an alpha-numeric code (HM742 .S63 2023, for example).

These codes are called "call numbers." Each book in the library has a unique call number. A call number is like an address: it tells you where the book is located in the library. Call numbers appear on the spines of books and bound journals.

These numbers are meaningful and correspond to subjects in the Library of Congress classification system. Using this system, books that are primarily about the same subject are shelved together. That means that you can often find several helpful books on the same shelf, or nearby.

Reading the number

Example Call Number. HM742 .S63 2023

First letters. The first letter of a Library of Congress call number indicates the general class the call number falls within. In the example above, the book is located under H, which is where books on the social sciences are classed. If there is a second or third letter, these indicate a specific subclass. HM, for example, indicates sociology.

Numbers that follow the letters. The numbers define the subject of the book. The number 742 refers to a book about social media, political participation, and group behavior.

Cutter number (the next set of numbers). The Cutter Number (.S63, for example) indicates the author or title of the book. It is taken from a table matching names or titles to a set of numbers.

Year number. The edition of a volume is the next part of the call number. The year of publication follows the Cutter number to indicate the edition. In our example, 2023 indicates that this edition was published in 2023.

Finding books on the shelves

Once you're on the right floor, note the labels on the shelves which show which call number ranges are on those shelves, then look for your call number on the spine of a particular book. Read the call number alphabetically and numerically, paying attention to the order of the letters and numbers (for example, H comes before HA and HM, and 741 comes before 742).

Getting help

Don't hesitate to ask for assistance at the Research Help Desk if you're having trouble finding a book or understanding the call number system.