Now out, and a reminder about the new translation of the Beitraege. The Heidegger of the '30s is my favorite by far.
The goal is to think "Beyng" - "Beying" rather than "Being" is an archaic spelling that Heidegger consciously borrows from Schelling and the German idealists. This means to step outside of the correlationist circle while admitting that the circle may be opened ancestrally within the being asking the question.
Perhaps stated differently: I find that in this book Heidegger seeks to "non-humanly" think from within the real - in a strange way, Dasein is not "human" at all.