A specialist in the cultural use of psychoactive plants, Christian Ratsch is the author of numerous books, including Gateway to Inner Space, The Dictionary of Sacred and Magical Plants, and the forthcoming Encyclopedia of Psychoactive Plants. A resident of Germany, he is currently serving as the president of the German Society for Ethnomedicine. Richard Evans Schultes is a Jeffrey Professor of Biology and Director of the Botanical Museum at Harvard University (Emeritus). He lives in Massachusetts. Albert Hoffmann, discoverer of LSD, is a retired research biochemist who lives in Switzerland.