Isaac Newton is known today as one of the most profound scientists to have ever lived. Newton's discoveries in physics, optics, and mathematics overturned a variety of fundamental beliefs about nature and reshaped science in ways that are still powerfully with us. But this is only part of Newton's fascinating story. Research over the last generation has revealed that the famous scientist spent over thirty years composing, transcribing, and expounding alchemical texts, resulting in a mass of papers totaling about a million manuscript words. In fact, Newton seems to have considered himself one of an elite alchemical brotherhood, even going so far as to coin private anagrams of his name in the secretive custom of the sons of art. Despite our growing knowledge of Newton's deep involvement in alchemy, one basic question remains to be answered Why did the founder of Newtonian physics believe in alchemy, a discipline long viewed as discredited in the modern scientific world? William R. Newman's lecture will attempt to arrive at an answer to that question by providing the evidence that led seventeenth-century thinkers to an acceptance of alchemical transmutation.