Tim O’Brien’s fictions twine around his truths until they form a tightly woven strand. The same threads alternately appear as reality or illusion, like the eyes of a dime store Jesus blinking open or closed according to the viewer’s perspective.

From a tour as a combat infantryman in the Vietnam War, O’Brien has manufactured a skein of tales. His novel In the Lake of the Woods, like many of its predecessors, derives its energy from uncertainty. It’s never clear what elements the author has appropriated whole from his experience and what he has fabricated from the cloth of his imagination.

The perfect O’Brien observation occurred in the story collection The Things They Carried. The narrator, whose name matched the author’s own, told the story of how, when he was drafted, he almost swam the Rainy River to Canada. Instead, he went to Vietnam, because he preferred to kill people rather than to be thought a coward. Things was grounded in such mundane admissions, as was O’Brien’s earlier Going After Cacciato, in which a platoon of GIs chased a deserter across the Indo-European landmass to Paris, and soared on the wings of fantastic realism.

Vietnam—a conflict where American participants spoke of life “back in the world,” as if the place where they were fighting were a separate planet—seemed in O’Brien’s eyes to be a war that defied the imagination while thriving in it, deriving strength from a capacity to establish the unbelievable as ordinary.

In the Lake of the Woods reverses that polarity. Its main character, veteran John Wade, is so determined to disbelieve the war’s quotidian horrors that he erases himself and his participation in it from the official record of the 1968 My Lai massacre, then constructs a life in which the war exists as a distant dream—until, as a middlingly successful politician, he overreaches and tears the seam of pretense. On the verge of a make-or-break primary, the My Lai connection surfaces, and Wade’s Senate campaign sinks like a body to the bottom of a glacial lake.

He and his wife repair to the Lake of the Woods near the Canadian border where the pre-authorial O’Brien contemplated the expatriate game but opted for his 13 months in-country. Both Wades are emotionally wounded, trying to find a path into the future but tangled in the complexities of the past. Kathy Wade disappears, engendering a massive police search across miles of featureless wilderness. John Wade remains curiously unemotional, stirring constabular curiosities.

At this point, glints of Wade’s soldier days begin to flash on the page like fragments of newsreel inserted into a film, grainy snippets of indictment suggesting that the war made Wade crazy. But as O’Brien peels the layers off the onion that is Wade (the name itself is evocative: “Waist Deep in the Big Muddy,” echoes of the Duke, intimations of burdens assessed), the picture becomes at once clearer and less sure.

For one thing, the narrator is a fictional character named…Tim O’Brien. The author again has drafted his fictional alter ego into service as a tunnel rat, pursuing the reality extant in matters imagined and the fakery implicit in truth.

Wade didn’t go crazy after Vietnam. He was on the way well before he arrived there, driven by an abusive, drunken, suicidal father and an obsession with sleight-of-hand. The war didn’t make Wade into something other than what he was any more than it made America into something other that what it was. What the war did was provide a setting in which the character and the country could become all that their coiled malevolence implied.

Safely ensconced in the constant danger of the war, Wade was free to adopt an alternate persona, street-named Magician; with the constant murderous attrition of patrols and firefights and the steady influx of new recruits, he molted his old name and his old self, slipping out of them like a shedded skin. As hundreds of thousands of new guys joined the war, America did the same.

Like the United States, Wade went to Vietnam to actualize something resident in himself. Just as it heated the nation to a malign catalysis, the war’s cauldron heated Wade to a personal boiling point, triggering a toxic reaction that required 12,000 miles and 25 years to reach completion.

Trading as it does in cruel memories and their far-reaching effects, In the Lake of the Woods is not an easy book. O’Brien’s lucid rendering of brutal events shreds the harmonizing haze of history from matters that have lost their dissonance. His hectoring reminders that all is rarely as it seems complicate his narration. At the novel’s close, the ghost of “Incident at Owl Creek Bridge” suffuses the figurative and literal fog into which O’Brien’s characters and story fade.

But ultimately John Wade’s story and the story of his wife’s disappearance meld, slubbed with interjections from O’Brien the character, who sometimes seems to be in an argument with O’Brien the author. The novel acquires a spectral glow, like the northern lights on the horizon of a Minnesota summer night: stubbornly unilluminating except in piercing instants, elusive, translucent, sometimes transfixing.