I have only browsed the volume, so for now I will just draw the attention to an introductory "notes for readers" which is freely accessible here, where Epp offers his own definition of the goal of New Testament Textual Criticism which he admits has varied, but as it stands now it is totally in line with my own view:
The Unitary Goal of New Testament Textual Criticism
New Testament textual criticism, employing aspects of both science and art, studies the transmission of the New Testament text and the manuscripts that facilitate its transmission, with the unitary goal (1) of establishing the earliest attainable text (which serves as a baseline), and at the same time (2) of assessing the textual variants that emerge from the baseline text so as to hear the narratives of early Christian thought and life that inhere in the array of meaningful variants.
Finally, I was also pleased to learn from the introduction "Developing Perspective" (accessible here) that Krister Stendahl from Sweden, then professor at Harvard University, gave the young doctoral student Epp the task to review a book on textual criticism by Fascher for the seminar and then with his other colleagues in the doctoral committee encouraged Epp to pursue a text-critical dissertation – well done! For another glimpse of Stendahl and a student at Harvard working on textual criticism in the 1950's, see here.