This work, the text of Martin Heidegger's lecture course of 1929/30, is crucial for an understanding of Heidegger's transition from the major work of his early years, Being and Time, to his later preoccupations with language, truth, and ...

I am trying...to go back through all those places where I was exiled-enclosed so he could constitute his there. To read his text to try to take back from it what he took from me irrecoverably...I am trying to re-discover the possibility of a relation to air. Don’t I need one, well before starting to speak?