This book examines Roger Bacon's alchemical theories, and explains how he believed that the key to extending life lay not in the curricula as taught in the medical faculties of the universities, but in the study of alchemy. Though twelfth- and thirteenth-century alchemy was generally concerned with the transmutation of metals, Bacon's alchemy was a much larger area of study, and encompassed the generation and corruption of all material things in the sublunary world. It was this aspect of alchemy, which Bacon referred to as speculative alchemy, that explained how the four elements of fire, air, water, and earth interacted with each other to make the basis of reality as man could know it. Thus, the study of alchemy in conjunction with humoral medicine could explain not only how the human body worked, but how it interacted with the materials around it, illuminating the method of prolonging life to extreme lengths.