In 1970, when Tracy Kidder came home from Vietnam, he wrote a novel about the war called Ivory Fields. It was about a lieutenant scarred by battle and abandoned by God; trying to save a native girl from rape, he earns the enmity of his men and dies at their hands. Kidder says 33 publishers rejected Ivory Fields, but it was fiction through and through. Its young author never intended to represent it as anything else, but he still imagined demurring as readers asked how much was autobiographical, and having them think that he must have gone through some hell in country. Maybe all war stories are lies, to some extent.

Kidder begins his astonishing new memoir My Detachment with Bill, a Vietnam vet, telling him a made-up story about a captain who made Bill leave his wounded buddy and the fragging that captain later received. The story so impressed Bill's audience that he embellished it for future listeners, heedless of its complete falsehood. Kidder spent his enlistment, and some time thereafter, telling lies in officers' clubs, letters home, and the fiction he thought was his life's calling. My Detachment unfolds like origami, layer upon layer of romantic illusions, tragic aggrandizement, naive idealism, and naked pain.

Famous for elegant non-fiction like The Soul Of A New Machine and Mountains Beyond Mountains, Kidder thought he was born for the novel while attending Harvard. When he was sent to Vietnam despite a cushy intelligence posting after ROTC, he was already anti-war. But his sentiments shared a bed with Hemingway's manly, stoic soldiers and Fitzgerald's lovelorn aesthetes. For his letters, he invented an "inscrutable but lovely" girlfriend, two Vietnamese orphan boys for whom he wrote bedtime stories, and numerous trips outside the wire. In truth, he was dreading inspections, enduring the petty tyranny of minor officers looking for scapegoats, and earnestly describing to anyone who would listen how much he respected the enlisted men.

My Detachment packs multiple levels of consciousness between its slim covers. The youthful officer watches himself inventing a soldier for the benefit of family and sweetheart, while the older memoirist watches himself trying to tell the truth about that young man. Anyone wondering how much of this memoir is a tale about a tale, a lie that works in the marketplace of war stories, has some company. Kidder wants to know too.