See W. R. Halliday, Greek Divination (1913, repr. 1967); W. B. and L. R. Gibson, The Complete Illustrated Book of Divination and Prophecy (1973).
Divination (from Latin divinare "to be inspired by a god", related to divine, diva and deus) is the attempt of ascertaining information by interpretation of omens or an alleged supernatural agency, either by or on behalf of a querent.
If a distinction is to be made between divination and fortune-telling, divination has a formal or ritual and often social character, usually in a religious context; while fortune-telling is a more everyday practice for personal purposes. Divination is often dismissed by skeptics, including the scientific community, as being mere superstition: in the 2nd century, Lucian devoted a witty essay to the career of a charlatan, Alexander the false prophet, trained by "one of those who advertise enchantments, miraculous incantations, charms for your love-affairs, visitations for your enemies, disclosures of buried treasure, and successions to estates, though most Romans believed in dreams and charms. It is considered a sin in most Christian denominations and Judaism.