Raising hopes of an effective treatment for mental illness, psychosurgery was widely practised throughout the Western world and beyond in the mid-twentieth century. While the history of the diffusion of this therapy, once seen as revolutionary, and the controversies it provoked are now fairly well known, the expansive field of practice still offers historians a vast amount of material to explore. By comparing scientific publications and patients’ medical records, this chapter provides an understanding of the history of the surgical treatment of mental pathologies in the main university hospital of the mental health system in north-eastern France, the University Psychiatric Clinic of Strasbourg. To do so, it combines an analysis of concrete statistical data with an illustration of the major principles, formally established or not, that guided the implementation of this therapy, while also questioning the conclusions transmitted by the main actors of this history.