This chapter explores Michel Foucault's contribution to a critical assessment of modern and contemporary psychiatric practice. It focuses firstly on theHistory of Madness(1961): the social, political, cultural, epistemological construction of the object "psychiatric patient" and "psychiatric pathology"; the gradual historical shift from "madness" to "psychiatric pathology" and its social and epistemological consequences; the horizons and limits of the romantic task Foucault assumes on this basis (namely, the idea of letting the voice of madness come back and speak again, "under" the language and categories of medical knowledge); the critique Jacques Derrida formulated (Writing and Difference, 1967) about this project, and particularly about Foucault's reading of Descartes. Secondly, it examines Foucault's course onPsychiatric Power(1975), focusing on the sociopolitical consequences of this medicalization process: i.e., the construction of the object "psychiatric patient" as "disciplinated bodies", and the general context of this anthropological metamorphosis Foucault studied in his booksDiscipline and Punish,The Will to Knowledge, and in his courseNaissance de la biopolitique(namely, the shift, during the last two centuries, from a disciplinary model to a biopolitical model of power and, more specifically, of administration of mental illness and mental health).