You can use Library Search and search by Author, Title, Subject, or Keyword.  Note location (Main, Art, Annex, etc.), call number, and availability. Use the Guide to Locations/Map (at Reference or posted around the Library) to find what room the call number is housed in. On the shelves, note that adjoining books are on closely related topics.

Use these call numbers to browse the Catalog or the Stacks:

BL700 - BL820 (Greek, Roman, Etruscan religion)
CC (Archaeology)
CN1 - CN753 (Inscriptions, Epigraphy)
PA (Latin/Greek language and literature)
DE (ancient Mediterranean world)
DF1 - DF289 (Ancient Greece)
DG11 - DG365 (Ancient Rome)