Oxford Classical Dictionary
The Oxford Classical Dictionary (OCD) is generally considered "the best one-volume dictionary on antiquity," an encyclopædic work in English consisting of articles relating to classical antiquity and its civilizations. It was first published in 1949 (OCD1 or OCD), edited by Max Cary with the assistance of H. J. Rose, H. P. Harvey, and Alexander Souter.
Source: Wikipedia — Oxford Classical Dictionary (CC BY-SA 4.0)