Why does O’Brien begin his book with an episode from Vietnam? What tone does the first chapter establish for the rest of the book? In your opinion, what is the prevailing attitude toward the Vietnam War in this first chapter

The first chapter serves to introduce O'Brien as the novel's narrator. His tone is frustrated..... fearful.... realistic. The war is frightening, and the exhaustion of O'Brien and his fellow soldiers amidst an unfamiliar terrain and invisible oppostion set the tone for the entire novel.