Shamanism ( /ˈʃɑːmən/ SHAH-mən or /ˈʃeɪmən/ SHAY-mən) is a term used in a variety of anthropological, historical and popular contexts to refer to certain magico-religious practices that involve a practitioner reaching altered states of consciousness in order to encounter and interact with the spirit world. A shaman is a person regarded as having access to, and influence in, the world of benevolent and malevolent spirits, who typically enters a trance state during a ritual, and practices divination and healing. The exact definition and use of the term "shamanism" has been highly debated by scholars, with no clear consensus on the issue.

The term "shamanism" originates from the Tungusic languages of eastern Siberia, and was originally used by western scholars to describe the practices of certain types of magico-religious specialist within Central and Northern Asia. Upon learning more about religious traditions across the world, western scholars also used the term "shamanism" in reference to similar magico-religious practices found within the indigenous religions of other parts of Asia, Africa, Australasia and the Americas. Various historians have argued that shamanism also played a role in many of the pre-Christian religions of Europe, and that shamanistic elements may have survived in popular culture right through to the Early Modern period. Various archaeologists and historians of religion have also suggested that shamanism may have been a dominant religious practice for humanity during the Palaeolithic.

Terence Kemp McKenna (November 16, 1946 – April 3, 2000) was an American philosopher, psychonaut, researcher, teacher, lecturer and writer on many subjects, such as human consciousness, language, psychedelic drugs, the evolution of civilizations, the origin and end of the universe, alchemy, and extraterrestrial beings.

Terence McKenna grew up in Paonia, Colorado. He was introduced to geology through his uncle and developed a hobby of solitary fossil hunting in the arroyos near his home. From this he developed a deep artistic and scientific appreciation of nature.

At age 16, McKenna moved to Los Altos, California to live with family friends for a year. He finished high school in Lancaster, CA. In 1963, McKenna was introduced to the literary world of psychedelics through The Doors of Perception and Heaven and Hell by Aldous Huxley and certain issues of The Village Voice that talked about psychedelics.

McKenna claimed that one of his early psychedelic experiences with morning glory seeds showed him "that there was something there worth pursuing." In an audio interview Terence Mckenna claims to have started smoking cannabis regularly during the summer following his 17th birthday.

Sandra Ingerman is a psychotherapist and shamanic practitioner who teaches workshops on shamanism. She has taught with Michael Harner, and was the Educational Director for the Foundation for Shamanic Studies, where she served on the Board of Trustees. Currently she serves on the Board of Directors of the Society for Shamanic Practitioners

Ingerman received her M.A. in counseling psychology from the California Institute of Integral Studies and is a licensed therapist and counselor in the state of New Mexico. She is a board certified expert on traumatic stress and certified in acute traumatic stress management. She has written books books including Soul Retrieval, Welcome Home, Shamanic Journeying and How to Heal Toxic Thoughts.

Soul Retrieval is a shamanic practice, popularized by Ingerman, which involves journeying to the spirit world to retrieve parts of the client's soul that have been lost as a result of trauma experienced earlier in life.

Alberto Villoldo, Ph.D., is a Cuban-born psychologist, anthropologist and author who has studied the shamanic healing practices of the Amazon and Inca shamans for over 25 years. He is the founder of The Four Winds Society, which offers a two-year long program in energy medicine and leads trips to Peru.

Villoldo graduated in 1969 with a bachelor's degree in Inter-American Studies, followed by a master's in Psychology (1972), and a doctorate in psychology at the Humanistic Psychology Institute. His thesis advisor was Dr. Stanley Krippner), a consciousness researcher and a pioneer in the study of the paranormal phenomena, with whom he later co-authored Healing States: A Journey Into the World of Spiritual Healing and Shamanism. While on the faculty of San Francisco State University, Villoldo founded and directed the Biological Self Regulation Laboratory at San Francisco State University, where he investigated the effects of energy healing on blood and brain chemistry.

Villoldo cites a number of key Shaman mentors, who shared their Shamanic knowledge with him through his years in Peru and the Amazon:

Moughenda Mikala is a 10th generation Missoko Bwiti Shaman and Nganga living in Costa Rica. He is the first indigenous Bwiti Shaman to bring the traditional use of Iboga and the Bwiti ceremonies to the Western world. He is known for specializing in spiritual healing and the use of Iboga as a way of detoxification and healing. He is the Founder and head Shaman of Iboga House in Costa Rica which is the first Bwiti run Iboga Treatment Center in the Western Hemisphere. He is the first Bwiti Shaman to speak on drug addiction for the Drug Policy Alliance. He was also featured in the 2009 documentary Manifesting The Mind which also featured John Major Jenkins and Terence McKenna.