With his famously controversial handling of the duration of psychoanalytic sessions, Jacques Lacan violated the standards of the International Psychoanalytic Association (IPA), which stipulate that psychoanalytic sessions must last exactly 50 minutes. Lacan viewed this as nothing more than a formalism, arguing that the speaking cure should be guided by the content of the patient's speech rather than the clock. Nicolas Langlitz examines this contentious technical innovation of the French psychoanalyst against the backdrop of Lacan's conception of the temporality of the subject. Drawing on a wealth of references and materials from philosophy and the history of science, as well as from the history of medicine and psychoanalysis, the book not only unfolds an engaging history of psychoanalytic treatment techniques but also reveals Lacan's demanding theoretical work through the lens of his practice.