This book addresses Foucault's transition from the notion of episteme to that of the apparatus of power. The former is a term coined in The Order of Things, referring mainly to the formation of knowledge in each era, given its conditions of possibility. As for the second notion, Foucault deals with it in shorter texts, but ones that are fundamental to understanding his thinking, since the concept of the apparatus of power makes it possible to relate the question of knowledge to the problem of power. The apparatus of sexuality is taken as an example of the possible articulation between the formation of knowledge and power games.