Locating a call number

Interpreting a Library of Congress call number takes practice. As an example, this page explains how to find the following engineering book:

TA658.44 A43 1999     Design for Earthquakes

While the call number appears on one line in the catalog, it will be broken into several lines on the book's spine label:


These are the steps to follow to locate this book:

  • First, find the row of shelves that holds books with the initial letters TA on the first line of the spine label. The letters are organized alphabetically, so TA follows T and comes before TB.
  • Next, look in the TAs for the number 658.44, which will be on the second line of the book's spine label. Pay attention to the decimal point. TA658.44 A43 will follow call numbers such as TA658 S83 that do not have this first decimal because 658.44 is greater than 658. Similarly, TA658.44 precedes TA658.48 and TA658.8 because 658.44 is smaller than 658.48 and 658.8.
  • Now look at the the third line of the label for the letter A.
  • The number following this letter is also treated as a decimal, which means that A43 comes before A5 and after A395 because .43 is less than .5 and greater than .395.
  • The final number, 1999, indicates the publication year and can help you distinguish the most recent edition from any earlier ones. Older books, however, may not have the publication year at the end of their call number.

See the LC classification schedule for a summary of the subjects designated by LC call number ranges.

If you have any difficulty finding a call number, please ask at the reference desk.