"If you look at the history of native people around the world, one of the striking things you will notice immediately is that nearly all early native cultures developed the concept of medicine work, or spiritual healing. Even more astonishing are the similarities of these healing techniques across cultures, even those cultures and tribes that could not have had any interaction with each other across great distance. While the modern term applied ot these spiritual healers is 'shaman', that term originated with the Tungus tribe of Siberia" (Harner 20).

- Harner, Michael. The Way of the Shaman. San Francisco, CA: Harper Collins, 1980

"In most cases, shamans enter non-ordinary reality (NOR) by ingesting a psychotrophic plant, or through the use of a steady drumbeat to alter brain function, and to achieve a Shamanic State of Consciousness (SSC). Other methods of entering the SSC are through fasting, sleep deprivation, physical exhaustion, hyperventilation, or temperature extremes, such as those experienced in a sweat lodge. Most shamanic practioners refer to three levels of NOR - the lower, middle, and upper realms. While a great deal of shamanic work occurs in the Upper and Middle worlds, most soul retrieval and extraction work occurs in the Lower world. It is in this realm that the shamanic practitioner is able to communicate with plants, animals, spirit guides and the non-living" (Wesselman 7).

- Wesselman, Hank, Ph.D. The Journey to the Sacred Garden: A Guide to Traveling in the Spiritual Realms. Carlsbad, CA: Hay House, 2003