Dr. Âke Hultkrantz was recognized as a major authority on Native American religions and shamanism. He was a professor of religion at the University of Stockholm, Sweden. During the years 1948 and 1958, Professor Hultrkrantz conducted field work at the Wind River reservation, which resulted in his ground-breaking book, Native American Religions of North America: The Power of Visions and Fertility. His other works include The Religions of the American Indians, Shamanic Healing & Ritual Drama: Health & Medicine in the Native North American Religious Traditions, and Belief and Worship in Native America.

He contributed the introduction to The Spiritual Legacy of the American Indian: Commemorative Edition With Letters While Living with Black Elk . Âke Hultkrantz died in October, 2006.