This article combines the disciplines of textual/linguistic analysis, anthropology, and perceptual psychology to examine selected ancient Jewish mystical texts that claim to describe the praxis for ascents into heaven and encounters with angelic spirits in order to reconstruct the psychosocial context of these literary works. Specifically, the article examines Hekhalot or "Divine Palaces" texts that deal with hydromancy, giving attention to their mythic–symbolic assumptions, their described preparatory and triggering rituals, and their accounts of the ASC (altered states of consciousness) visions (...) resulting from these rituals that are experienced by the practitioners. The article suggests that these accounts correlate with ASC practices identified in the literature and additionally suggests that although the mystical texts are written to resemble biblical accounts of revelatory experiences, the texts under consideration are more than works of fabulous imagination; they are literary artifacts of an actual ecstatic ASC praxis among the Jews of Late Antiquity. (shrink)