Ludwig Binswanger, a founder of the existential school of psychiatry, attempted to apply philosophical ideas derived from Martin Heidegger, such as Heidegger's views on the mind-body problem, to the understanding and treatment of psychiatric patients. Binswanger also interpreted Heidegger's concept of the existing individual (Dasein) as Being-in-the-World, in the sense of seeking out the existential structure of individuals' lives. I discuss concrete clinical cases from Binswanger's work, along with a contemporary example of how to use these existential methods in psychiatric practice.