Dugan Library uses Library of Congress Classification (LCC) for our collection. This means that call numbers will look different than you might expect if you are accustomed to Dewey Decimal Classification (DDC).
This guide will provide a general overview of the LCC classes and major subclasses. While not every subclass will be covered, see the links on the class pages of the guide if you need more detailed information.
Here is an example of the call number for the book The Achievement of John Henry Newman by Ian Turnbull Ker.
| BX | Class Letter(s): The first letter(s) in a Library of Congress call number references the subject class for that object. The first letter is class and adding a second letter indicates a subclass. In this case, B is the letter for the class "Philosophy, Psychology, Religion" and BX is the subclass "Christian Denominations." Items are shelved alphabetically by these letters first, before looking at the next element. |
| 4705 | Numbers Following Class Letters: The numbers after the class letters indicate the specific subject within the class or subclass. In this case, 4705 within subclass BX refers to "Biography and portraits -- individual saints." These numbers may also have decimal places. Within class letters, items are next shelved numerically according to this element. |
| .N5 K44 |
Cutter Number(s): A cutter number will be a combination of a letter and number. There may be one or multiple cutter numbers. The first cutter number will always be preceded by a period (additional cutter numbers are not). Cutter numbers can reference several different things, including a subtopic, geography, an author name, or the work title. In this case, N5 refers to Newman, the subject of the work and K44 refers to Ker, the author of the book. Items with the same class numbers are shelved according to cutter number alphabetically, then numerically (i.e. the cutter .N5 would go before .N6, but after M.2). |
| 1990 | Year Number: While not always included, the final element of the call number will often be the publication or copyright date. Items with otherwise identical call numbers, are shelved chronologically by this date. |
Here are a selection of books from the medicine class (R) in the order that they would be shelved* (from left to right):
|
R |
RC 78.5 .R33 2011 |
RC 133 .G6 J64 2006 |
RG |
RJ 245 .N856 2007 |
*There are lots of books between each of these books in the collection.