Using Library of Congress Classification Call Numbers
Step 1 - Finding the Call Number:
When you search the library's catalog, your results for physical items housed in the Lyman Beecher Brooks Library will often include a Location listing and a Library of Congress call number:
Search Result: 
The "Location" listing will direct you to the appropriate floor, collection, or service desk where you can retrieve the item.
The "Call #" listing is the Library of Congress call number for that item that will lead you to the item's exact shelf location.
Step 2 - Breaking Down the Call Number:
Now that you have a call number, breaking it down into its parts will tell you not only about the item's location but also the topic that the item is classified under.
Starting from the top of the call number, when written on a spine label as shown above:
- The first line is the class or subclass and is represented in letters:
- Call numbers are in alphabetical order moving from left to right and top to bottom on the shelves. A full listing of the classes/subclasses that may be used on the first line can be found here: Library of Congress Classification Outline
- Call numbers are in alphabetical order moving from left to right and top to bottom on the shelves. A full listing of the classes/subclasses that may be used on the first line can be found here: Library of Congress Classification Outline
- The second line is the topic and is represented as a number:
- Within the class, topics are ordered by numbers (including decimals if included) counting up from zero by moving left to right and top to bottom on the shelves.
- Within the class, topics are ordered by numbers (including decimals if included) counting up from zero by moving left to right and top to bottom on the shelves.
- The next line(s) - there may be one or more lines between the topic number above and the publication date line below that begin with a decimal point followed by a letter then numbers or a letter followed by numbers. These lines narrow the topic, specify the author, or identify the title of the work:
- First, read the letter. Next, read the numbers as a decimal number moving left to right. For example: .C75, .C76, .C77, .C778, .C78 is the proper shelf order.
- First, read the letter. Next, read the numbers as a decimal number moving left to right. For example: .C75, .C76, .C77, .C778, .C78 is the proper shelf order.
- Publication date and additional lines:
- The last line is usually the item’s publication date, however there may also be a line for the copy number, volume number or other additional information line. These are read left to right in numerical order.
Note: Library of Congress Classification call numbers are assigned to items based on their topic. This means that if you find a book that you are interested in on the shelf, you may want to browse the shelf to the left and right of your item for related materials.
Step 3 - Locating the Item on the Shelf:
Now that you have a call number from your item search, a general location in the building, and an understanding of how to read the call number, it is time to head to the shelves.
You will encounter call numbers in the stacks written in two ways, as a single line and in multiple lines. When reading a call number written as a single line, split the letters and numbers of the class and topic (BX4406.5 becomes BX 4406.5) then read the spaces as line breaks to translate them to the multiple line format. Or, vice versa, to translate from multiple line to single line format:
- Single line (such as in search results and on the ends of shelf rows):
- Multiple lines (such as on a spine label on a book):
To find your item on the shelf, go to the location specified in your item record from your search, locate the shelves with the correct range call number using the signs on the ends of the shelves, then locate the spine label of your item on the shelf by following the call numbers to its exact location.
If you need any assistance, please contact any library staff member and we will be happy to assist you!
Special Collections / Exceptions:
Some items, such as those in the Herbert A. Marshall Collection, require the assistance of library staff and will direct you to the First Floor Circulation Desk.
Example: 