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.

Michael Harner (born 1929) is the founder of the Foundation for Shamanic Studies and the formulator of "core shamanism." Harner is known for bringing shamanism and shamanic healing to the contemporary Western world. Walsh and Grob note in their book, Higher Wisdom, "Michael Harner is widely acknowledged as the world's foremost authority on shamanism and has had an enormous influence on both the academic and lay worlds…. What Yogananda did for Hinduism and D. T. Suzuki did for Zen, Michael Harner has done for shamanism, namely bring the tradition and its richness to Western awareness." Harner received a Ph.D. in anthropology from the University of California at Berkeley in 1963. He taught there and at Columbia University, Yale University, and the Graduate Faculty of the New School for Social Research, where he chaired the anthropology department. He also co-chaired the Anthropology Section of the New York Academy of Sciences. In 1987 Harner left academic anthropology to devote himself full-time to the preservation, study, and teaching of shamanism as president of the non-profit Foundation for Shamanic Studies. In 2003 he received an honorary doctorate for his work from the California Institute of Integral Studies. In 2009 two sessions on shamanism were given in his honor at the annual meeting of the American Anthropological Association. He received the 2009 Pioneer in Integrative Medicine Award, Institute of Health and Healing.

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.

Ralph Metzner Ph.D. (born May 18, 1936 in Germany), is an American psychologist, writer and researcher, who participated in psychedelic research at Harvard University in the early 1960s with Timothy Leary and Richard Alpert (later named Ram Dass). Dr. Metzner is a psychotherapist, and Professor Emeritus of psychology at the California Institute of Integral Studies in San Francisco, where he was formerly the Academic Dean and Academic Vice-president.

Dr. Metzner has been involved in consciousness research, including psychedelics, Yoga, meditation and Shamanism for over 45 years. He is a co-founder and President of the Green Earth Foundation, a non-profit educational organization devoted to healing and harmonizing the relationship between humans and the Earth, and a signatory to the 9/11 Truth Statement. Metzner was featured in the 2006 film Entheogen: Awakening the Divine Within, a documentary about rediscovering an enchanted cosmos in the modern world.

He has conducted numerous workshops on consciousness transformation and alchemical divination, both nationally and internationally. He is also a poet and singer-songwriter and has produced one CD.