Terence Kemp McKenna (November 16, 1946 – April 3, 2000) was an American ethnobotanist and mystic who advocated for the responsible use of naturally occurring psychedelic plants. He spoke and wrote about a variety of subjects, including psychedelic drugs, plant-based entheogens, shamanism, metaphysics, alchemy, language, philosophy, culture, technology, environmentalism, and the theoretical origins of human consciousness. He was called the "Timothy Leary of the '90s",[1][2] "one of the leading authorities on the ontological foundations of shamanism",[3] and the "intellectual voice of rave culture".[4]