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Library of Congress Classes & Shelving: What does the call number mean?

In the Catalog

When call numbers appear in the LNDL catalog, this is what they look like:

Catalog record


For this item, there are two holdings records because two libraries have it - us and Hood. The top call number (BF199 .Z88 1985) is for our holdings.

LOC Call Numbers

Remember how we told you that every Library of Congress (LOC) call number starts with a letter?  Well, that first letter tells you a lot about what the subject of the book (or other item) is:

  • A - General Works
  • B - Philosophy, Psychology, Religion
  • C - Auxiliary sciences of history
  • D - World History
  • E-F - History of the Americas
  • G - Geography, Anthropology, Recreation
  • H - Social Sciences
  • J - Political Science
  • K - Law
  • L - Education
  • M - Music and Books on Music
  • N - Fine Arts
  • P - Language and Literature
  • Q - Science
  • R - Medicine
  • S - Agriculture
  • T - Technology
  • U - Military Science
  • V - Naval Science
  • Z - Bibliography, Library Science

Now, of course, there's more to an LOC call number than the first letter!   But that first letter is the most basic element in the call number, and most libraries divide up their collections into distinct areas based on these initial letters (more on that in the "where in the library?" tab).

Let's consider a sample call number - E491 .W76 2006. What do all the parts mean?

E 491 .W76 2006

'E' of course means it has to do with History of the Americas, as you can see in the general subject table above. The following number, 491, indicates that it's specifically United States history because it falls between 151 and 909 (491 happens to be the Civil War).  Then the .W76 is the author 'Cutter' number, which comes from the author's last name (Wilson).  The final element, 2006, is just the date of publication.

Some call numbers are much longer than this for various reasons, usually having to do with how specialized and/or complex the item's subject is.  But hopefully this gives you some idea of what an LOC call number is, and why they look the way they do.

But now - how do we find it?  Go on to the next tab to find out!