Laboratory examples of reality dreams, followed by a rough classification of such dreams according to the prevalence of a predominant somatic sensation, are described below. This chapter illustrates how dream effects-and above all reality dream effects-can be discerned in the literature on spiritual belief. A small selection of examples are reviewed to demonstrate that reality dreams, identifiable by their expressions of intense somatic imagery, have been implicated in the development of beliefs in malevolent other-than-human beings. Three examples of how reality dreams affected witchcraft beliefs are discussed: dream phenomena during witch-hunts of the Inquisition, the dream origins of beliefs in white witchcraft, and dream-based witchcraft beliefs in African culture. Traditions of dream incubation in ancient Greece bear a close similarity to traditions of dream-vision quest among the early North American Indians. The possibility that realism in dreaming alters waking spiritual beliefs is supported by literature reviewed in this chapter.