Much of Duhem’s work as a professional scientist was closely related to the newly emerging discipline of physical chemistry. The book and associated papers translated here revolve around his concomitant philosophical and historical interests in chemistry topics. Duhem understood contemporary concerns of chemists to be a development of the ancient dispute over the nature of mixture. Having developed his historical account from distinctions drawn from the atomists and Aristotelians of antiquity, he places his own views of chemical combination squarely within the Aristotelian tradition.