A Prolegomena to the Activity of Reading Husserl

In the Preliminary Part of the Prolegomena to the History of the Concept of Time Heidegger has this to say about the creation of the Logical Investigations:

"This work on the fundamental objects of logic occupied Husserl for more than twelve years. The initial results of this effort from the contents of the work which appeared in two volumes in 1900-1901 under the title Logical Investigations. This work marks the initial breakthrough of phenomenological research. It has become the basic book of phenomenology. The personal history of its origin is a story of continual despair, and does not belong here." (p. 24)

This dates from 1925, two years before what can only be considered the next "basic book of phenomenology" would be published. Of course, as anyone who has glanced through LI would realize, the version that we have comes from 1913 when Husserl made his first attempt to revise what he considered unsatisfactory elements of the text, no doubt relating at least somewhat to the immense difficulty LI poses the reader. Whether or not this relates to the "continual despair" Heidegger refers to I don't know; however Husserl was clearly aware of the challenges of LI. In the notes to the Introduction to Part II he says:

"Our investigation can, however, only proceed securely, if it repeatedly breaks with such systematic sequence, it it removes conceptual obscurities which threaten the course of investigation before the natural sequence of subject-matters can lead up to such concepts. We search, as it were, in zig-zag fashion, a metaphor all the more apt since the close interdependence of our various epistemological concepts leads us back again and again to our original analyses, where the new confirms the old, and the old the new." (p. 175)

Thus, we have before us a text that was miserable to produce and is challenging to read. Take that as you will.