For much of the past four decades - from Oaxaca to the Amazon - ethnobotanist Dr. Mark Plotkin has been studying the medicinal fungi and plants used by indigenous healers. He serves as the President of the Amazon Conservation Team which has partnered with over 100 South American cultures to map and improve management of 90 million acres of ancestral rainforests. And he has written five books on biodiversity and health, the most recent of which was The Amazon - What Everyone Needs to Know (Oxford Press). Mark also hosts the popular podcast, "Plants of the Gods: Hallucinogens, Healing, Culture and Conservation."