The best place to find books on ancient history is the Library Catalog.
Some subject headings to start with: History, Ancient (with various subheadings) will find many general works
For Greece:
Greece--Antiquities--[various subheadings]
Greece--Civilization--[various period and topical subheadings]
Greece--History--[various period and topical subheadings]
Example: Greece -- History -- Peloponnesian War, 431-404 B.C
If you are interested in the Ancient Near East, you can search Egypt with the same subheadings. You can also search directly for the names of people, cities, or events.