Necromancy ( Latin necromantia, Greek νεκρομαντία nekromantía) is a form of divination in which the practitioner seeks to raise the spirits of the dead in order to gain knowledge of future events from them, or to acquire special powers from such entities. The word derives from the Greek νεκρός nekrós "dead" and μαντεία manteía "divination". It has a subsidiary meaning reflected in an alternative and archaic form of the word, nigromancy, (a folk etymology using Latin niger, "black") in which the magical force of "dark powers" is gained from or by acting upon corpses. A practitioner of necromancy is a necromancer.
Necromancy may or may not have a relation to shamanism, which calls upon spirits such as the ghosts of ancestors.
The historian Strabo (Strabo, xvi. 2, 39, νεκρομαντία) refers to necromancy as the principal form of divination amongst the people of Persia; and it is believed to also have been widespread amongst the peoples of Chaldea (particularly amongst the Sabians or star-worshippers), Etruria and Babylonia. The Babylonian necromancers themselves were called Manzazuu or Sha'etemmu and the spirits they raised were called Etemmu.
In the Odyssey (XI, Nekyia), Odysseus makes a voyage to Hades, the Underworld, and raises the spirits of the dead using spells which he had learnt from Circe (Ruickbie, 2004:24). His intention was to invoke the shade of Tiresias, but he was unable to summon it without the assistance of others.
There are also many references to necromancy in the Bible. The Book of Deuteronomy (XVIII 9–12) explicitly warns the Israelites against the Canaanite practice of divination from the dead. This warning was not always heeded: King Saul asked the Witch of Endor to invoke the shade of Samuel, for example.