Arguing for the thematic and structural unity in Heideggers thought from Being and Time right through to the later writings, this book focuses on the summons to authenticity; labeling the move as the key to identifying recurring patterns and themes in Heideggers protracted confrontation with modernity. Heidegger's thinking in the decades following the publication of Being and Time is often deemed irreconcilable with that work. Critics contrast the notion of resoluteness. in Being and Time with Heideggers post-war account of releasement in an attempt to establish a discrepancy between the allegedly voluntarist humanism of his early work and the supposedly anti-humanist thinking of his later work. By contrast, Mahon O Brien argues for the structural and thematic coherence of Heidegger's movement from authenticity to the search for an authentic free relation to the world as captured by the term releasement. By demonstrating the structural and thematic unity of Heidegger s thought in its entirety, O Brien paves the way for a more measured and philosophically grounded understanding of the issues at stake in the Heidegger controversy.