Few books are more convincing rebukes to the seemingly never-ending age of the memoir and all its attendant cults of authenticity than William Maxwell's So Long, See You Tomorrow. Maxwell carves this slender, graceful and (above all) heartbreaking novel out of a single, unforgettably awkward moment: On his first day at high school in the 1930s, shortly after his family moved from the small central Illinois town of Lincoln to Chicago, he saw -- and ignored -- a boy in the corridor who had been a passing childhood playmate. The boy, whom Maxwell calls Cletus Smith, left town after his father had gunned down the tenant farmer who lived next door, a man named Lloyd Wilson, before killing himself.

But Maxwell doesn't use this lurid tale to launch on the kind of self-dramatizing sleuthing that has made the memoir more of a recovery workbook than a literary genre. Instead of proclaiming some ready-made saving wisdom or foreshadowing a catharsis, he makes plain that his own painful memories are not to be trusted: "In talking about the past," he writes, "we lie with every breath we draw."

Yet Maxwell is drawn inexorably back to the awful story that cast Cletus Smith out of Lincoln, largely because of his simple failure to acknowledge Cletus in that high-school hallway that day -- or any day afterward. Writing as a much older man, Maxwell rues this typical adolescent (and American) retreat from a social encounter involving unthinkable suffering, while also knowing that any gesture he could have made would have done precious little good.

Maxwell tracks the meaning of this silent slight across not just the tangled story of the Smith and Wilson families -- which, unsurprisingly, revolves around a scandal of marital infidelity -- but also into the no less sad tale of his own family's past. His mother died giving birth to his younger brother in the midst of the 1918 flu epidemic, plunging his father into a kind of "sadness . . . without patience or hope." Eventually, Maxwell's father remarried, but as the Maxwell clan reconstituted itself, young William kept resolutely fixed on its former incarnation: "Now was the moment to forget . . . about the void that could sometimes be bridged and dreams, and about the way things used to be when my mother was alive." Maxwell writes that he clung to them "more tightly than ever, even as I was being drawn willy-nilly into my father's new life."

Small wonder, then, that for both Maxwell and the Cletus Smith he imagines in the pages of the novel the idea of a house -- that most sturdy marker of family stability and simple belonging in a place -- becomes a talismanic symbol of childhood worlds that can never be recovered. The set piece from which the book derives its title takes place on the site where the Maxwell family was building a new house: There Cletus simply turned up one day, and the two boys fell into the kind of reflexive camaraderie natural to boys from damaged domestic circumstances. "I never asked Cletus if there wasn't something he'd rather be doing, because he was always willing to do what I wanted to do. It occurs to me now that he was not very different than an imaginary playmate." Yet soon enough, Cletus vanished in the wake of his family's final collapse, and Maxwell grew up and migrated East, ending up as a longtime fiction editor of the New Yorker. When he returns to Lincoln, he gravitates to his first family home there "as if it was a sexual temptation." Of course, after changing hands several times it all looks wrong to Maxwell now -- he remains in thrall as ever to the lie of the past. He dreams of houses his family didn't live in, and intuits that his birth mother is inside them, alive and well. And he imagines an open-air palace where he can meet Cletus Smith and nod once more in recognition, a place "where what is done can be undone."

So Long, See You Tomorrow has many such quiet moments of suspended animation; Maxwell's generous, unsentimental voice keeps it from succumbing to the twin temptations of easy nostalgia and mere fatalism. It is far too modest to be a palace, but it does offer a remarkable vantage on the perpetual, never trustworthy works-in-progress that are our remembered lives. I look forward to discussing it on Thursday, June 24, at 3 p.m., at www.washingtonpost.com/bookclub.