Finding a Book in the Library

WR3 | Workshops

Finding a Book in the Library

Finding a book (or other physical resource) on the shelf of the library isn’t as easy as it sounds. This is a guide to help you understand how libraries are organized and find books you need for your research.

Library Classification Systems

Libraries use classification systems to organize their holdings. The most common in the English-speaking world are the Dewey Decimal Classification (DDC) and the Library of Congress Classification (LCC) systems. There are a number of other library systems. In Europe, for example, you will encounter the Universal Decimal Classification (UDC) system. But like most research libraries in the US, Dartmouth’s libraries use the Library of Congress system.

The Library of Congress organizes all knowledge into a system of 21 basic subjects, each associated with a single letter of the alphabet. For example, the letter B is used to identify philosophy, psychology, and religion. Each of these subjects may be further refined with the addition of other letters. For example, BC is the subclass for Logic and BQ is the subclass for Buddhism. These subclasses may be refined even further with an alphanumeric code that represents a very specific research focus. When all of these letters and numbers are placed in a specific order, they form a unique code that is known as the book’s call number. The call number is listed in the book’s entry in the library’s catalog so that you may locate it on the shelves, or “stacks,” as they are known.

The Anatomy of a call number

To find a book’s location in the library stacks, you need to know its call number. The Library of Congress assigns every copyrighted book a unique call number consisting of a series of numbers and letters that help you locate them on the library’s shelves and indicate the subject matter contained within it. A typical call number will resemble the following:

Let’s break down the call number into its constituent parts:

Call Number Name Purpose or Use
F Letter line
24 Whole number line
  • Indicates a narrower subtopic within a discipline or subject.
  • Tells you which row the book is on in the stacks.
.T39 Cutter line
  • Identifies the individual book.
  • The first letter of the Cutter line is usually the first letter of the author’s last name.
1990 Edition/Date line
  • Tells you the book’s year of publication.
  • May also include volume or edition information after the year.

Steps to find a book on the shelf

Method A:

Step 1: Letter Line

F 24 .T39 1990

Use the letter line to determine the floor of the library where the book is shelved. The library’s floorplan maps will help you locate the proper section. Using our example call number above, we can determine that the F section is in Stack Level A.

Step 2: Whole Number Line

F 24 .T39 1990

Once on the appropriate floor, use the whole number line to find the row where the book is shelved in the stacks. Using the example call number, we will look through the stacks for the number 24. Each library floor has a floormaps to help guide you; they are available in .pdf form or are posted on the wall of each floor, near the entrance.

As you walk through the stacks, look on the ends of each row for signs describing the range of books held within the row such as the one below:

{ Use these signs to determine if a book is in the row. }

Since F 24 is within this range, our example book is in that row. Once in the proper row of shelves, proceed numerically until you find the 24s.

Step 3: Cutter Line

F 24 .T39 1990

Finally, using the Cutter line, proceed alphabetically until you hit the Ts. Then proceed numerically until you find .T39, the address of our book.

  • The date or volume information at the end of a call number will only be useful to you if you are looking for a particular edition of a book.

As you can see, the call number should be read from left to right using alphabetical and numerical orders. Thus, a book with a Subject line F would be shelved before a book with a Subject line FA. Similarly, a Cutter line that reads .T39 is shelved after .T21.

Maps of the library’s floorplans are affixed to the walls on each floor. Free paper maps of the library are available at the circulation desk of the library. You may also consult the maps and floorplans online with your computer or smartphone.

Method B:

Or Just Forget All That

A new update to Dartmouth’s catalog as of 2014 allows you to simply click the “map it” button next to the item’s listing in the catalog.

Clicking this button will summon a map that shows you the approximate location of the book in the library stacks.


In a normal year when you are on campus and there is no pandemic, I would assign you each a book to find in the shelves and ask you to post a selfie with it in the stacks. But since most of you are not on campus, this will not be possible.

Instead, find some book that you have lying around the house and locate it in our online catalog. Using the call number, try to find the exact location of of this book using the two methods described above.