The Oxford History of Greece and the Hellenistic World edited by Boardman, Griffin, and Murray
This book includes chapters devoted to Greek mythology, philosophy, drama, historians, religion, art, and Homer.
The Oxford History of the Classical World edited by Boardman, Griffin, and Murray
Information about Classical literature, philosophy, religion, and more. The book also features maps and illustrations.
The Oxford Classical Dictionary edited by Simon Hornblower and Antony Spawforth
The OCD has the distinction of being one of the most comprehensive studies of the Classical world.