Necromancy is a special mode of divination by the evocation of the dead. Understood as nigromancy (niger, black), which is the Italian, Spanish and old French form, the term suggests "black" magic or "black" art, in which marvellous results are due to the agency of evil spirits, while in "white" magic they are due to human dexterity and trickery. The practice of necromancy supposes belief in the survival of the soul after death, the possession of a superior knowledge by the disembodied spirit, and the possibility of communication between the living and the dead. The circumstances and conditions of this communication — such as time, place, and rites to be followed — depend on the various conceptions which were entertained concerning the nature of the departed soul, its abode, its relations with the earth and with the body in which it previously resided.
Necromancy is the act of conjuring the dead for divination. It dates back to Persia, Greece and Rome, and in the Middle Ages was widely practiced by magicians, sorcerers, and witches. It was condemned by the Catholic Church as "the agency of evil spirits," and in Elizabethan England was outlawed by the Witchcraft Act of 1604.
Necromancy is not to be confused with conjuring devils or demons for help. Necromancy is the seeking of the spirits of the dead. The spirits are sought because they, being without physical bodies, are no longer limited by the earthly plane. Therefore, it is thought these spirits have access to information of the past and future which is not available to the living. It has been used to help find sunken or buried treasure, and whether or not a person was murdered or died from other causes.
The practice of necromancy has been compared by some to modern mediumistic or practiced spiritualism. Many consider it a dangerous and repugnant practice. Dangerous because it is alleged that when some spirits take control of the medium they are reluctant to release their control for some time.