In the period covered by this volume, the disciplines of architecture and science were far closer than they are today. According to the seventeenth‐century author John Evelyn, not only was architecture part of science and mathematics, it could, in theory, represent the apogee of those practices. As all writers on architecture in this period agreed, it was amongst the most useful applications of mathematical and scientific knowledge. Yet architecture's place amongst the early modern sciences was a complicated and contested one and the analysis of the early modern science/architecture relationship comes with many potential pitfalls. These problems primarily stem from the insecure disciplinary status of both science and architecture in the period. As we shall see, it is no exaggeration to say that science, as a coherent intellectual category, did not exist before the nineteenth century. Add to this the problems of defining architecture as a profession in the period and the task of the historian becomes doubly difficult. This chapter will carefully set out these problems in some detail before introducing the reader to various ways in which historians have attempted to overcome them. Much of the discussion will focus on the final years of the seventeenth century and the beginning of the eighteenth century. This was a critical period in the histories of both science and architecture, but it also represented the apex of their intellectual relationship. Later into the eighteenth century, architecture retained its close allegiance with surveying, building technologies and engineering but perhaps lost forever its affinity with more pure forms of science.