Part of the fascination of Being and Time is that it seeks to weave together so many different strands of thought. But unsurprisingly, its readers also worry that such a work must subject itself to such strain that ultimately it itself must unravel. Key tensions are between the outlooks of three figures: Heidegger the pragmatist, Heidegger the existentialist, and Heidegger the philosopher of being. Seeing how openness to our concerns as a whole is both necessary for authenticity and reveals a unified horizon against which entities with different ways of being show themselves, dissipates these apparent tensions. Recognition of the mediating role played by a conception of the good – that Heidegger’s reading of Aristotle and Augustine inspired – helps make clear that authenticity is both compatible with the practical embeddedness of our concerns and reveals a form of understanding necessary for ontology to be possible.