As an administrative tool of police reform, the introduction of house numbering in eighteenth-century Geneva was the result of a broad desire for urban transparency that resulted in the production of a new 'regime of visibility'. This article examines how the logic of 'number' transformed the way in which urban space was conceived, organized and governed. As a political technology, the spatial practice of house numbering enabled governmental officials to divide, count, identify and classify urban populations in order to regulate the spaces of circulation in the modern city. Although the city's house-numbering system is taken for granted by most of the town-dwellers today, the current study illustrates how these police techniques encountered considerable resistance when they were initially imposed during the latter half of the eighteenth century.The practice of house numbering was adopted in cities and towns across Europe in the mid-eighteenth century with such rapidity that it is not an exaggeration to regard it as a cornerstone of urban modernity.1 As a typical product of the Enlightenment, the production of calculable spaces of 'number' seduced governmental officials who embraced the abstract order of numerical identification, because it was potentially legible and understandable to all users of urban space, including those least familiar with a given place.2 The numerical co-ordinates of house-numbering systems indicate and assign a place for individuals and property in the city. Consequently, the street address becomes, like the passport, a medium of personal identity.3 A commonplace object of everyday life for more than