How does the chapter contribute to the theme of guilt?

In “Notes,” the narrator speaks very candidly about his own narrative tricks. Again he calls attention to the fact that the book is fiction. But even the writer O’Brien does have certain emotions: he is anxious that the reader understand he is not trying to dishonor his fellow soldier. Because it is taken out of the context of “Speaking of Courage” and placed in a purportedly non-fictional chapter (complete with accurate dates of publication of the author’s other works), Bowker’s suicide has the ring of authenticity. This gives the event an even deeper impact, perhaps, than had it been included at the end of “Speaking of Courage.” In O’Brien’s dichotomy, it is a “happening-truth” rather than a “story-truth.”