The aim of this special issue is to question, starting from Michel Foucault, the link between the epistemological reflection on mental health and the historicity of the knowledge that defines it. Elisabetta Basso's contribution draws on Foucault's manuscripts of the 1950s, in order to analyze how the young Foucault initiates a reflection that leads him to radically put into question social sciences. Ugo Balzaretti discusses the relationship between psychoanalysis and biopolitics, which he explores in the light of the archaeology of psychoanalysis developed by Foucault in Naissance de la clinique and Les mots et les choses, but also in the genealogy of power outlined in La volonté de savoir. Laurent Dartigues’s article deals with the way in which Foucault reads and uses psychoanalysis – whose presence in Foucault’s corpus does not only concern the writings of the 1950s and 1960s – but remains constant throughout the philosopher's work, with an uncertain and fluctuating status. Aurélie Pfauwadel dwells on a stumbling block that concerns one of the genealogies of psychoanalysis outlined by Foucault, the one that, in the 1970s, put Freudism on the side of normalization. Clotilde Leguil focuses on Lacan’s thinking, by emphasizing its political dimension in that it promotes an anti-identitarist conception of the subject. Finally, the dossier presents the transcription of an unpublished manuscript by Foucault on psychoanalysis, in which the philosopher intends to assess the contribution of psychoanalysis to the understanding of mental illness.