The notion of expertise has received a lot of attention recently from historians and other scholars. Of special interest has been the relationship between the expert and the state, and in particular the appropriate role for the expert to play in settling public debates about science and technology within modern democracies. While this work has focused almost exclusively on the modern era, the roots of many of the issues, debates, and institutions under consideration go back many centuries to the early modern period. Reliance upon the practical knowledge and skill of experts was a key factor in enabling early modern states to become more powerful and sophisticated and to construct empires and economies that were global in reach. At the same time, the state was an important source of legitimation and status for the experts who served it. By examining the nature of expertise and its relationship to the early modern state, as both entities evolved together and reinforced one another, historians can acquire a more comprehensive understanding of both.