Birth of a Metropolis examines the transformation of Naples over the long eighteenth century and the consequences of that transformation for the sorts of knowledges produced by Neapolitans about their city. First, it documents the astonishing rate at which the capital city of Naples grew and the territorial expansion required to accommodate that growth. At the same time, this study shows that the capital not only outgrew its political confines, or città, but grappled to make sense of the moral order of a city that was larger than its political territory and more diverse than its citizenry. Thus, this study suggests that the demise of the city as both a bounded political entity and as a codified field of civic behavior made the development and application of the human sciences not only compelling but also instrumental within what was one of Europe’s most dynamic and protean capital cities.