Every war novel must at some point confront a central contradiction. Only the truth has any real value, but the truth about war is that it contains nearly unbearable levels of repetition, boredom and meaninglessness. To write honestly about war, you should make readers feel they have endured those things as well. Yet no sane novelist wants to inflict that much discomfort on the audience. And so we read novels (and watch movies) filled with the kind of bravery and drama that make war look at least entertaining, if not admirable. Many of those works are tremendous artistic achievements. But they’re not war.

Karl Marlantes’s first novel, “Matterhorn,” is about a company of Marines who build, abandon and retake an outpost on a remote hilltop in Vietnam. According to the publisher, Marlantes ­— a highly decorated Vietnam vet — spent 30 years writing this book. It was originally 1,600 pages long; now it is 600. Reading his account of the bloody folly surrounding the Matterhorn outpost, you get the feeling Marlantes is not overly worried about the attention span of his readers; you get the feeling he was not desperate or impatient to be published. Rather, he seems like a man whose life was radically altered by war, and who now wants to pass along the favor. And with a desperate fury, he does. Chapter after chapter, battle after battle, Marlantes pushes you through what may be one of the most profound and devastating novels ever to come out of Vietnam — or any war. It’s not a book so much as a deployment, and you will not return unaltered.

The story is told from the point of view of a young second lieutenant, Mellas, who joined the Marines for confused and vaguely patriotic reasons that are quickly left in tatters by military incompetence. At great psychic and physical cost, Mellas and the rest of Bravo Company, Fifth Marine Division, climb a steep mountain near the intersection of Laos and the DMZ separating North and South Vietnam, then build an outpost capable of withstanding enemy artillery. As soon as they finish, they are told to abandon it because they are needed for a large operation farther south. There ensues a multiweek stagger through impenetrable jungle, the company plagued by lack of food, lack of ammunition and inadequate resupply. One man is killed by a tiger. Another dies of cerebral malaria. Starving to death and bearing a dead friend on a pole, the men of Bravo Company finish their mission and are allowed a brief rest at one of the main support bases.

Image Khe Sanh, 1968. Credit... Tim Page/Corbis

Soon enough, however, they are ordered to retake Matterhorn, which has since been occupied by the enemy. It is there, on the flanks of their own outpost, that the horror and absurdity of war are finally played out. “After three hours of debate they finally realized that there was no perfect plan,” Marlantes writes as the company plots its assault. “Somebody was going to get killed.” The battle scenes are vivid, devastating and vaguely repetitious — surprisingly, the only parts of the book where my mind started to wander. But combat is not really what “Matterhorn” is about; it is about war. And in Marlantes’s hands, war is a confusing and rich world where some men die heroically, others die because of bureaucratic stupidity, and a few are deliberately killed by platoon-mates bearing a grudge. In one of the more remarkable passages of the book, Mellas contemplates the killing that goes on in nature and struggles with the question of whether it is evil:

“No, the jungle wasn’t evil. It was indifferent. So, too, was the world. Evil, then, must be the negation of something man had added to the world. Ultimately, it was caring about something that made the world liable to evil. Caring. And then the caring gets torn asunder. Everybody dies, but not everybody cares. It occurred to Mellas that he could create the possibility of good or evil through caring. He could nullify the indifferent world. But in so doing he opened himself up to the pain of watching it get blown away.”