Finding Books:
Using Library of Congress call numbers 

Each book (or other item in the library catalog) has its own unique call number.  Think of a call number as an address for a particular book on the shelf.  Call numbers are assigned according to a book's main subject, and books about the same subject have similar call numbers, making it easier for you to browse the library's holdings on a specific topic.

The book's call number appears on or near the spine of the book.  The call number also appears in CLICnet, the library catalog.  Once you have located the entry for a specific book in CLICnet, make a note of it and then look for the book in call number order on the library shelves (also called "the stacks.")

The University of St. Thomas Libraries, like many academic and research libraries, uses call numbers based on the Library of Congress Classification System.  This system uses a combination of letters and numbers to arrange materials by subject.  The first line in a Library of Congress call number classifies the item by its subject according to the Library of Congress Classification System.  The entire call number should be noted in order to locate the item.

• LC call numbers are first arranged alphabetically, according to the letter or letters at the beginning of the call number, which corresponds to the subject matter of the item. 
  Example:  Call numbers beginning with H are followed by HA, HB, HC, etc.         
• Within the alphabetical section, books are arranged by the number(s) that follow.  Notice that these numbers are regarded as whole numbers.  Example:  HD 69 before HD 108 before HD 108.55 before HD 108.6                
• The next lines are alphabetic, and then numeric as a decimal, not a whole number.  The alphabetical order is used first, then the decimal number to put the call numbers in the correct order.  (S634 would come before S7, because .634 is smaller than .7.)
  Example:  HD 6060.3 .S634 before HD 6060.3 .S65 1984                            
• Different editions are often arranged by date or by date and letters.
  Example: HD 6060.3 .S65 1984 before HD 6060.3 .S65 1999 before HD 6060.3 .S65 1999a

See also:

How to read a call number