This book tells the comprehensive history of cosmography from the 15th Century Age of Discovery onward. During this time, cosmography—a science that combined geography and astronomy to inform us about our place in the universe—was deeply tied to ongoing developments in politics, exploration, culture, and technology. The book offers in-depth historical context over nearly four centuries, focusing in particular on the often neglected role that Portugal and Spain played in the development of cosmography. It details the great activity emerging from the Iberian and Italic peninsulas, including numerous voyagers of exploration, a clear commercial intention, and advancements in map-making techniques. In doing so, it provides a unique perspective on the “Longitude problem” not available in most other literature on the topic. Rigorously researched and sweeping in scope, this book will serve as an invaluable source for historians and readers interested in the history of science, of astronomy, and of exploration from a southern European perspective.