Book excerpt: The book offers convincing evidence to incorporate the Catholic world of early modernity into the history of modern science. The research is supported by the analysis of not widely studied primary sources such as the sixteenth century Iberian nautical manuals. Through the use of theoretical frameworks such as the Actor Network Theory, the book sheds light on the need to incorporate the role of heterogeneous human actors and artifacts (ships, navigation tools, sails, cannons), natural and geographical agents (ocean currents, winds, the sun, the moon and the stars), and divine entities (gods, daemons and saints) into the political history of early modernity.