Introduction, chapter I: The Necessity, Structure, and Priority of the Question of Being
As suggested by its title, ch.1 aims to demonstrate:
The necessity of the Seinsfrage: In other words, H wants to clarify the challenges of answering it, and to do so well enough to show that it’s a genuine question that oughtn’t be dismissed out of hand. This is what H tackles in section 1.
The structure of the Seinsfrage: Here, H argues, partly on the basis of some general considerations having to do with the nature of inquiry, for a certain approach to clarifying the question. Namely, he argues that in order to answer the Seinsfrage, we have to undertake a certain sort of inquiry into ourselves. This is what H tackles in section 2.
The priority of the Seinsfrage: Here, H argues that the question ought to be of interest to philosophers, because an answer to it is necessary for an adequate answer to many other traditional philosophical questions. Specifically, it’s necessary for a proper approach to two major themes of philosophy: the nature of scientific inquiry, and human nature. This is what H tackles in sections 3 and 4.