Books at Holy Cross are organized by Library of Congress (LC) call numbers. Call numbers allow librarians to (1) organize books on the shelf by topic, and (2) give each book a unique "address" that can be used to locate it in the library. Each letter and number in a call number refer to information about the book's topic.
Here is a tutorial on reading call numbers: HC Libs Survival Guides #1: Call Numbers
Call numbers beginning with A through G are on the upper (Mezzanine) level of Dinand. Call numbers H through Z are on the lower (Ground) level of Dinand, with some exceptions. Books with call numbers starting with M are located in the Music Library. Books with call numbers starting with Q, R, S, and T are located in the Science Library. Reference books in Dinand are located in the Main Reading Room.
The map below shows where call numbers are located within Dinand Library. Dinand also has paper maps of the stacks.