Demonology, and the Occult

Demonology is the study of demons or beliefs about demons, especially the methods used to summon and control them. The original sense of "demon", from the time of Homer onward, was a benevolent being, but in English, the name now holds connotations of malevolence.

Demons, when regarded as spirits, may belong to either of the classes of spirits recognized by primitive animism. That is to say, they may be human, or non-human, separable souls, or discarnate spirits which have never inhabited a body.