It is difficult to be precise about just how the emergence of the psychological sciences in the nineteenth century was linked up to other political and social events. This difficulty is compounded by the problem of grasping what actually does differentiate these sciences from those religious, philosophical, and medical discourses on human mental life which preceded them. In this chapter I suggest that these issues become clearer when placed in the context of ‘governmentality’. The national political territories in Europe and North America in the late nineteenth and early twentieth centuries were traversed by programs for the governing of increasing areas of social and economic life in order to achieve desired objectives: security for wealth and property; continuity, efficiency, and profitability of production; public tranquillity, moral virtue, and personal responsibility. These programs were not unified by their origin in the state, or by the class allegiances of the forces that promoted them or the aims they set themselves. As we shall see later, they were as heterogeneous in conception and support as they were diverse in their strategies and mechanisms. What did characterize these programs, however, was the belief in the necessity and possibility of the management of particular aspects of social and economic existence using more or less formalized means of calculation about the relationships between means and ends: what should be done, in what ways, in order to achieve this or that desirable result.