Herodotus tells us that when Croesus, the king of Lydia, asked the Delphic Oracle whether he should attack the Persians, he was told that if he did so he would destroy a great empire. Delighted, he proceeded with the invasion, but the empire that he destroyed was his own. This story gives some sense of the enigmatic power that oracles held in the ancient world, and indeed they were consulted as revered sources of guides from archaic times until late antiquity (and in some cases even later). Richard Stoneman's learned and accessible study explores what made the Greeks in particular consult oracles, drawing comparisons with Egypt and other ancient cultures. He considers related questions such as divine-sent dreams and healing, and the development of new attitudes to oracles as religion and philosophy evolved. The abolition of all pagan rites in 395 AD saw the official end of this practice, but Stoneman shows how Christianised oracular prophecies survived for centuries to come.