Intellectual developments pioneered by scholastic natural philosophers of the fourteenth century constituted a critical stage in the emergence of scientific thought. Beneath these technical developments lay a profound reconceptualization of nature. The purpose of this book is to analyze the components of this reconceptualization, and to speculate on the influences that shaped it. It argues that the transformation of the conceptual model of the natural world c. 1260-1380 was strongly influenced by the rapid monetization of European society during the same period.