Terence McKenna (November 16, 1946–April 3, 2000) was an 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, ethnomycology, environmentalism, and the theoretical origins of human consciousness. As a young man he had a very interesting life. When he grew older he wrote and lectured.