In the early 1950s, the young Michel Foucault took a keen interest in the method of existential analysis - Daseinsanalyse - developed by the Swiss psychiatrist Ludwig Binswanger. He gave a lecture course on this topic at the University of Lille in the spring of 1953 and wrote a detailed introduction to the 1954 French translation of Binswanger's Dream and Existence (1930), in which he promised a forthcoming book that would "situate existential analysis within the development of contemporary reflection on man." This book presents Foucault's unpublished manuscript on Binswanger and existential analysis for the first time in English, offering crucial insight into his intellectual development.