This volume allows English-speaking readers to take part in an encounter between the German philosopher, Martin Heidegger and the Swiss psychiatrist Medard Boss. A product of their long friendship, this book chronicles their exchange of ideas. Heidegger sought to transcend the bounds of philosophy while Boss and his colleagues in the scientific community sought an enduring intellectual foundation for better understanding their patients and their world. The work affords a unique opportunity to see how Hiedegger clarified and elaborated his central themes for an audience beyond the confines of philosophy - and to see how this audience inspired him to pursue new ideas and new directions. During World War II, Boss came upon Heidegger's ""Being and Time"". Intrigued by both author and book, yet conscious of the damning characterization of Heidegger as a Nazi sympathizer, Boss the physician nonetheless approached Heidegger the philosopher asking for help in reflective on the nature of Heidegger's thought. A correspondence ensued, followed by visits that soon became annual two-week meetings in Boss's home in Zollikon, Switzerland. The protocols from these seminars, recorded by Boss and reviewed, corrected and supplemented by Heidegger himself, make up one part of this volume. They are augmented by Boss's record of the conversations he had with heidegger in the days between seminars and by excerpts from more than 250 letters that Heidegger wrote to Boss between 1947 and 1971. In this book Heidegger attempts to make the fundamental ideas of his philosophy accessible to nonphilosophers. He addresses certain philosophical/psychological theories for the first and only time, including Freudian psychoanalysis and Indian philosophy.