Thesis and Conclusion: our asking “Why is there being rather than Nothing?” is a historical process and in that process opens us to different vistas. Heidegger concludes, “Being is the basic happening which first makes possible historical Dasein amid the disclosure of the essent as a whole” (Heidegger 201).
So what is “being?” It is permanence, already-thereness, given–enduring presence (202). When we ask “why is there essents rather than nothing,” our questioning is itself placed midway between being and nonbeing (29).
Whenever being is delimited, it is determined. There are four basic delimitations (becoming, appearance, thinking, ought). This constitutes the longest and most difficult chapter of the book. Simply put, being is permanent presence, becoming is emerging appearing, thinking is The breaking out, the agon, opens essent as sea, earth. It happens as language is mastered in violence (157). Knowledge: techne, putting into work the being of any particular essent. Truth is unconcealment. Unconcealment is the space created for the appearing of essent.
This book is difficult because it isn’t always clear where Heidegger is going. Nevertheless, while it can’t replace Being and Time, it represents a clear advance on some of the concepts.
Incidentally, Heidegger sees National Socialism (which he calls a great movement) as embodying the encounter between global technology and modern man, 199).