Christian Rätsch, Ph.D., is a world-renowned anthropologist and ethnopharmacologist who specializes in the shamanic uses of plants. He is the author of Marijuana Medicine and The Encyclopedia of Psychoactive Plants and coauthor of Plants of the Gods. Claudia Müller-Ebeling, Ph.D., is an art historian and anthropologist and coauthor, with Christian Rätsch, of Shamanism and Tantra in the Himalayas, Witchcraft Medicine, and Pagan Christmas. Both authors live in Hamburg, Germany.