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Reading Library Call Numbers

Library of Congress System at the Forrer Learning Commons

Currently, librarians are working to switch all of the library's materials to the LC system.

In the Forrer Learning Commons, the Library of Congress classification system is located at:

  • A–M: Upper floor
  • M–Z: Lower floor
  • Reference A–Z: Main (ground) floor

Finding LC Materials on the Shelf

LC has a lot of classes, so it can be a little overwhelming when you're trying to find a book, and it operates a little different than Dewey Decimal system. LC operates line-by-line.

The first line on the spine label will be the class and subclass, so they will be letters, such as MA or PR. You read this all at once, so P comes before PR, which comes before PS. 

While reading line-by-line with the classes can be easy, it gets a little trickier with the numbers in the second line, as you have to remember to take the whole number at a time. For example, 62 comes before 63, which comes before 623.

The third line with a letter and number is the same way. .S63 will come before .S64, which comes before .S632, which comes before .T63.

The final line is in order of publication date, so the earlier materials will be to the left, and the newer materials will be to the right.

As an example, a shelf with LC classification could look like this:

P
123
.S12
2010

PR
123
.S12
2010

PR
213
.S12
2010

PR
1234
.S12
2010

PR
1234
.S13
2010

PR
1234
.T1
2010

PR
1234
.T1
2020

Sometimes it can be really difficult to find an LC item on the shelf, so please feel free to ask us at the Circulation Desk for help should you need it in locating a book.