SHAMAN'S PATH: HEALING, PERSONAL GROWTH AND EMPOWERMENT, compiled and edited by Gary Doore is a well researched book about shamanism with no less than 16 PhDs, one MD and one MA contributing to this collection of writings. For a well researched view of what shamanism is, this is the book to read. More doctors and therapists are discovering that the shaman's methods are effective for healing and self discovery. Published in 1988, it is available on Amazon.
http://www.amazon.com/Shamans-Path-Healing-Personal-Empowerment/dp/0877734321/ref=sr_1_1?ie=UTF8&qid=1424301855&sr=8-1&keywords=shaman%27s+path
http://www.amazon.com/Shamans-Path-Healing-Personal-Empowerment/dp/0877734321/ref=sr_1_1?ie=UTF8&qid=1424301855&sr=8-1&keywords=shaman%27s+path