"Science of Man" in Heidegger's Zollikon Seminars was meant to serve as the foundation of the Daseinsanalyse in order to develop a new kind of psychoanalytic therapy, designed by Heidegger and to be implemented by Medard Boss. The present book investigates the scope of the Daseinsanalyse and its model for a new "science", which could follow either the path of serenity or the one of experience, producing by this means two different kinds of therapy: one turned to the transformation of man into Da-sein, the other dealing primarily with man suffering and ontic problems. To achieve this purpose, one will have to find out how Heidegger defines "science", "man", "anthropology" and "science of man" itself. Furthermore, the author suggests that a good example of how a daseinsanalytic approach to psychoanalysis could work is to be found in an ontic therapy, like the psychoanalysis of Winnicott.