If I Die in a Combat Zone: Box Me Up and Ship Me Home is an autobiographical account of writer Tim O'Brien's tour of duty in the Vietnam War. Published in 1973, it was one of the first major autobiographical accounts of the Vietnam War and has been praised extensively for its unflinching look at the horrors of armed conflict. Many critics have called it among the greatest pieces of literature to come out of the U.S. involvement in Vietnam.

O'Brien served a year in Vietnam, from 1969 to 1970. He makes clear from the beginning of the book that he was always opposed to the war in Vietnam, viewing it as pointless and not worth the loss of life. However, the book makes frequent note of the bravery of the young soldiers drafted into the jungles of Southeast Asia, even as it explores their doubt and fear unflinchingly.

In general, the book proceeds in chronological order, save for at the beginning. The first chapter starts in Vietnam, with O'Brien and a fellow soldier, Barney, lying motionless while bullets whiz over their heads. The chapter is disorienting, as the time and location are not named. It is obviously Vietnam, but when Barney asks where exactly they are, O'Brien says, "Tell them St. Vith," naming a town in Belgium that was part of World War II’s Battle of the Bulge (5). This opening puts readers in the situation of a soldier, disoriented and anxious, while also illustrating that even though the specific conflict may change, the emotions war elicits in soldiers do not.

The rest of the book is in something close to chronological order. O'Brien turns back to his childhood in Worthington, Minnesota and examines how he ended up in Vietnam. He explores his family's patriotism, and that of his hometown's. The Korean War unfolded during his early childhood, which increased the military's influence during his early years. Nonetheless, O'Brien decided in high school that he was against the Vietnam War.

Before he shows up for induction into the Army, O'Brien considers fleeing to Canada, but he doesn't go through with his plans. The story proceeds to O'Brien's experiences in basic training at Fort Lewis, in Washington state, where his anti-war beliefs lead him to bond with a fellow soldier named Erik. The two soldiers meet to talk about literature and war. They clash with their drill sergeant, Blyton, who scorns them as "college pansies" (36). In basic training, O'Brien again considers desertion, making plans to go to Canada or Sweden; he doesn't follow through on these plans, and instead goes to Vietnam.

On arrival in Vietnam, in 1969, O'Brien receives further military training in mine-sweeping, grenade throwing, and the tactical elements of jungle warfare. He is then assigned to Alpha Company in Landing Zone Gator, where he meets Captain Johansen, who is portrayed as a smart, brave authority figure respected by his men. A central theme of this part of the book is the fear of death. Unlike in World War II, where the action was generally confined to direct battles, the jungles of Vietnam are booby-trapped with mines and the soldiers need to be aware of the danger with every step they take. O'Brien focuses heavily on the various types of mines they encounter and the constant danger they present. Many of O'Brien's fellow soldiers meet their end in this manner, and the book never really focuses too much on any soldiers other than O'Brien. They simply pass through his wartime experience, and many don't make it home.

Towards the conclusion of the book, If I Die in a Combat Zone deals with the moral complexity of the war, as well as the legal ramifications thereof. When a local village that Alpha Company was protecting is accidentally shelled, O'Brien is offered a job at the rear and is airlifted out of the combat zone. He encounters a battalion executive officer, Major Callicles, who is involved in the investigation into the My Lai Massacre. O’Brien is employed as a typist under his command. Callicles is a stern, by-the-book officer, determined to do an honest and full investigation into misconduct by his own men, but he sees himself as a soldier on a crusade to fight the modernization and liberalization of the U.S. military. The stress of the investigation and its conflict with his belief that the U.S. military is the most honorable one on Earth weigh on the man as the investigation gains more and more attention.

The book ends with O'Brien leaving Vietnam, boarding a plane for home, and arriving in Minnesota. He observes the dull depression that seems to fill the plane, which epitomizes the morally-complex, hopeless way he viewed the war as a whole. Unlike many memoirs of wartime service, If I Die in a Combat Zone does not end with a sense of victory. Instead, O'Brien sees himself as a cog in a machine, serving a war that he never believed in and that he's unsure if the U.S. can win.

At the time O'Brien's book came out in 1973, direct U.S. military involvement in Vietnam had just ended. Thus, If I Die in a Combat Zone is considered a vanguard in the genre of Vietnam memoirs, with the unflinching look at the day-to-day life of a soldier and the skeptical eye he cast on the war influencing many future writers. Although O'Brien's book has never been adapted into a movie or TV series like other Vietnam memoirs, it has remained consistently in print for over forty years, a testament to its popularity.