WRIT 1150 Library Toolkit

Call numbers are essentially specific addresses assigned to books and other physical materials to make it easier to organize and find materials. Georgetown Library primarily uses the Library of Congress (LC) Classification System to number its books. Below is a quick primer to help you understand how to read LC Call Numbers so that you can go from a record on screen to a book in hand.

Call numbers on the screen will appear horizontally in a single row while call numbers on the spine of a book are typically listed vertically in chunks. For example, the call number for the Daniel Horowitz's book Happier?: The History of a Cultural Movement that Aspired to Transform America appears as follows in the HoyaSearch record:

HN57 .H59 2018

The same number appears vertically on the book's spine label:

HN
57
.H59
2018

See below for information on how to interpret this combination of letters and numbers.

HN
Read the first line in alphabetical order:
A, B, BF, C, D, DA, ... L, LA, LB, LC, M, ML...

57
Read the second line as a whole number:
1, 2, 3, 45, 100, 101, 1000, 2000, 2430...

.H59
The third line is a combination of a letter and numbers. First read the letter alphabetically, and then read the number as a decimal, e.g.:
.F64 = .64, .C724 = .724

Note: Some call numbers have more than one combination letter-number line. In those cases, read them in the same manner as you would read the third line.

2018
The last line is the year the book was published. Read in chronological order:
1843, 1972, 2010…

What if I need help?

If you need assistance reading call numbers, please reach out to the library for help.