This chapter examines the complex life and legacy of R. Gordon Wasson (1898–1986), arguably the most important figure in the explosion of interest in psychedelic mushrooms during the latter half of the twentieth century. A banker by trade, Wasson achieved huge international fame when he began to explore the use of Psilocybe mushrooms in the religious practices of Mexico and published his article, “Seeking the Magic Mushroom,” in Life magazine in 1957. He soon expanded his exploration of psychedelic fungi into a kind of global mushroom mysticism that he believed could be found everywhere from Siberia to ancient Greece and India, perhaps revealing the origins of religion itself. Yet Wasson’s research was also deeply problematic; he deceived the Mazatec wise woman who showed him the ritual use of mushrooms, publishing her photo and name against her will, and his work on Vedic and other materials is not taken seriously by many scholars today. To conclude, I will discuss the ambivalent legacy of Wasson’s work in the twenty-first century, both in the study of mysticism and in the medical and pharmaceutical industries, where corporations are now investing millions of dollars in research on psychedelic mushrooms.