"If I Die in a Combat Zone" is a personal memoir. In twenty-three brief chapters, Tim O'Brien recounts his experience as a young man drafted into military service during the Vietnam War. With thoughtfulness and insight, he illustrates his inner turmoil over his opposition to the war, and his struggle to decide whether or not to dodge the draft or to flee basic training. With the vulgar humor of a foot soldier, O'Brien brings to life the foxholes and night marches through the villages and minefields of Vietnam. He bares his soul in an examination of courage, justice, and the brutal behavior of infantrymen in the Vietnam War.

The memoir briefly recounts Tim O'Brien's childhood and education. This serves to help the reader understand what O'Brien stands to lose if he does not report for duty as called for by his country. The personal history also serves as a stark juxtaposition to the harshness of basic training and advanced infantry school where O'Brien is forced from the comfort of his hometown into military fatigues and a multiple occupancy barracks.

In advanced infantry training, O'Brien makes one last effort to seek counsel for his opposition to the Vietnam War. When he finds no guidance, he makes another effort to desert military training. O'Brien makes it to Seattle, but cannot bring himself to get on the bus and cross the border into Canada. Instead, several weeks later and despite his personal opposition, he lands in Cam Ranh Bay, Vietnam.

In Vietnam, O'Brien is assigned as a radio operator in Alpha Company. He is initiated into the life of a soldier in a combat zone. It is a rough and violent life. O'Brien survives many battles by burying himself in the mud. He watches the forest. He witnesses atrocities committed upon the Vietnamese. He sees many friends die. And he discovers a hero in his company commander, Captain Johansen. O'Brien takes the reader through the villages and battles of Alpha Company in each part of Vietnam, from the Batangan Peninsula to the My Lai.

The memoir closes with O'Brien safely ensconced in a non-combat position at a base camp. At this base camp, O'Brien finally manages to escape the most serious horrors of war, except introspection. Self-examination, O'Brien learns, can be as painful as combat. When O'Brien finally makes the return trip home to the plains of Minnesota, he is unable to rejoice. He left Minnesota as a college boy, but he returns as a man, irreparably affected by the Vietnam War.