‘Building a world of science’ outlines how early modern scientific thought was applied to the real world problems of the day. The emergence of gunpowder on the battlefield made castles obsolete, so new scientific knowledge was used to rebuild fortifications. This led to an increase in mining research to support these rebuilding programmes. Voyages to America precipitated developments in cartography, navigation and timekeeping. Formal scientific societies developed alongside universities, followed by less formalized salons and coffeeshops. These developments ultimately led to a professionalization of scientific work, and the development of a scientific career and social class.