Let me begin with a somewhat provocative remark:
The edition of the Nachlaß of a scientific author is not a goal in itself, but only a means to an end in achieving a certain goal or collection of goals.
The question consequently is: What was our goal in deciding to publish a significant part of David Hilbert's Nachlaß? In answering this question, I will draw on the many discussions conducted in the formative stages of the project, i.e., before the Hilbert Edition properly speaking was underway, as well as discussions held during the Edition's subsequent evolution. Let me stress at the outset, however, that what is presented here is the author's point of view, and does not necessarily reflect that of the other editors. Two meta-remarks are necessary to prevent obvious misunderstanding of the initial remark above.
First, note that reference was made quite consciously to the Nachlaß of a scientific author, as opposed to the papers and documents of an important literary figure, for example...