IRIS 42: Information and Research Instruction Suite for two-year colleges

Library of Congress Call Numbers

Used by academic and research libraries

Let's say you are looking for the book called Guts: Companies that Blow the Doors off Business as Usual.

Search the title in the library catalog to find the call number: screen shot of a record from the book catalog, with the call number circled

Library of Congress Call Number in Detail

Library of Congress Call Number, HD57.7 .F744 2004


The most important line to understand is the first line. In Library of Congress, the letters in the first line represent the subject of the book.

Call numbers are arranged using an alphanumeric system, meaning you follow both alphabetic and numeric order to find books.
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The first line of an LC call number starts with 1, 2 or 3 letters. These letters represent the subject of the book.  Find HC alphabetically on the shelves. HC comes after H, HA, HB. The second line makes the call number more specific. Once you locate call numbers that start with HC, look for the second line in numerical order. The third line makes the call number even more specific. After locating books with the first two lines, zoom in on the third line, first finding the F, then 744. Library of Congress call number line 4, 2004, is the date.