Library Instruction

Library of Congress Classification and Call Numbers

Call Numbers

Call numbers are assigned to materials based on their subjects and determine where materials are shelved.

Call numbers appear horizontally in the library catalog, but vertically on the spine label (the sticker on the book spine.)

A call number starts with a row of 1, 2, or 3 letters, then a row of numbers, then a row with a decimal point, a letter, and some numbers (which are treated as decimals) and maybe more rows. When looking for a book on the shelf, just start at the top and work down. And if you don’t find it, ask for help!

The row of letters relates to the subject:

The Library of Congress Classification System