When you have located a book you want, it is important to record the call number (if it is a print book, ebooks will have a link to the full text in the item record in Omni), for the call number is like an address as to the exact location of the book on the library's shelves :
Call numbers in academic libraries are based on the Library of Congress (LC) Classification system. This A to Z classification scheme organizes books by main subject, so that books on similar topics will be shelved together. Once you have located the book you want on the library’s shelves, you can browse the shelves in the same area for additional books on your topic. Clicking "Locate" provides information about the library, floor, and general area where the item is shelved.
The following is a partial breakdown of the Library of Congress Subject classification for “H” Social Sciences:
Sociology, HM, can be further broken down into subjects within the broader subject of sociology:
The first letter of a call number represents one of the 21 major divisions of the Library of Congress Classification System. The subject "H" is General Social Sciences. The second letter "M" represents a subdivision of the social sciences, Sociology. All books classified in the HM's are primarily about Sociology.