There is the art world; and then there is art. How much has one to do with the other? This is a question most readers of this magazine have probably asked at some point during their journey through late twentieth- and early twenty-first century cultural life, with its commodification of the new, the outré, the painstakingly “transgressive.” For decades now we have watched Chelsea and Soho tastemakers struggle to “find a balance,” as the novelist Michael Cunningham puts it, “between sentiment and irony, between beauty and rigor, and in so doing open a crack in the substance of the world through which mortal truth might shine.”

Cunningham is one of those valuable novelists who is just as interested in ideas as he is in literary aesthetics, and in his new book, By Nightfall, he grapples with both: aging, the meaning and importance of art, the search for untouched beauty in a tainted world. His protagonist is the Soho version of Everyman. Peter Harris is a successful art dealer who has just turned forty-four. Not one of the most successful; “If he doesn’t step up soon, he can probably expect to grow old as a solid, minor dealer, respected but not feared.” He wears pretentious eyeglasses and lunches only at the trendiest bistros. His wife, Rebecca, edits an arts and culture magazine called Blue Light. Their Mercer Street loft is a prototype for bohemian bourgeois luxe, interchangeable with any number of other “cutting edge” abodes of our era: “The Chris Lehrecke daybed, the Eames coffee table, the austerely perfect nineteenth-century rocking chair, the Sputnik-inspired fifties chandelier that keeps (they hope) the rest of it from seeming too solemn and self-important. The books and the candlesticks and the rugs. The art.”

Peter is just another Bobo in Paradise, it would seem. And yet . . . something is missing: that something that great art provides and that Peter is definitely not getting either from the art valued in his milieu (Cunningham has introduced a clever scene describing visitors at the Met blindly passing by “The Bronze Age,” Rodin’s magnificent male nude, as they make their obligatory pilgrimage to the now-canonical Hirst shark) or from his careful, careerist clients. There is Bok Vincent, who wraps his paintings in brown paper and then coats the paper in paraffin, in a vague reference to the shrouded Christ: the paintings inside cannot be seen, a hint that the art we anticipate is always superior to the art we create. There is Roger Groff, who does large bronze urns, “classical at heart but given pomo proportions,” covered with tiny, obscene hieroglyphics—aimed to insult the very collectors who avidly buy the works. And there is Victoria Hwang, who makes short videos of ordinary people in the street and then installs them, complete with action figures, lunchboxes, etc. that feature these same unremarkable passersby.

Yes, something surely is missing. Is this really the epicenter of cultural America, this corner of Prince and Broadway, this “Blade Runner strip mall, with its mammoth suburban chain stores?” And the view from Peter’s Mercer Street window at midnight—“streetside piles of black garbage bags and shrill little boutiques that come and go”—is that really the most expensive vista, per square foot of real estate, in the nation? A visit to Groff’s studio in a scuzzy and most definitely uninspiring Bushwick neighborhood gives Peter pause. He wonders:

Does the fringey urban semi-exile in which most artists live affect their output? Sure, young artists are expected to be poor, they’re supposed to be poor, but the poor artists of other generations lived in Paris or Berlin or London, they lived in Greenwich Village. . . . Yes, they lived meagerly, but they lived in places of real if decaying beauty. . . . In a place like this, wouldn’t it seem a little . . . silly to think about producing earnest work that aspired, however imperfectly, to the profound?

In the spirit of people getting the government they deserve, has America gotten the art it deserves?

The aridity Peter experiences is both aesthetic and spiritual: like Tosca he has lived for art, but art seems to have escaped his clutches. “Please, God, send me something to adore,” he prays. And it is at this moment that a fitting catalyst arrives in the form of Rebecca’s much younger brother. Born to middle-aged parents, his nickname is Mizzy—short for “Mistake.”

Peter has never much liked Mizzy, a feckless former drug addict who seems incapable of settling down as a useful member of society. Now, though, at this precarious emotional moment, Mizzy’s beauty touches Peter’s essence. He is the Rodin bronze come to life. He is the mirror image of Rebecca, her lost youth magically restored. He is the reincarnation of Peter’s brother Matthew, who died of aids twenty-five years earlier. And more and more to Peter, he is art, the elusive essence of it.

Isn’t this part of what you keep looking for in art—rescue from solitude and subjectivity; the sense of company in history and the greater world; the human mystery simultaneously illuminated and deepened; by Giotto’s expelled Adam and Eve, by Rembrandt’s final self-portraits, by Walker Evans’s photos from Hale County. The art of the past tried to give up something like what’s happening to Peter right now—a look into the depths of the human other. Videos of passersby aren’t the same. Nor are obscene urns or dead sharks or anything, really, that’s wry or detached or ironic, that’s meant to shock or provoke.

Peter, a lifelong heterosexual, becomes obsessed by the ethereal Mizzy, who holds out to him the possibility of a great, redeeming love. He feels that with Mizzy he too might become a Rodin bronze: not the Met beauty, he doesn’t deceive himself to that extent, “but not a Burgher of Calais either; he could be an undiscovered Rodin, the aging but unbowed, a figure of stern dignity, standing foursquare, weaponless, bare-chested. . . .”

It is not always easy to distinguish the fake from the genuine, either in life or art. Peter, who had always admired the Bok Vincent wrapped canvases, goes through a minor crisis of confidence when a studio accident reveals the hidden painting beneath one of the brown paper shrouds: it turns out to be a clumsy student work, a badly digested Philip Guston and Gerhard Richter rendered ineptly. This comes as a surprise to Peter—on some level he had believed in the artifact’s false promise—but it will not surprise the reader. What about Mizzy? Will his hidden soul, under its glittering outer wrapping, turn out to be as banal and second-rate as the revealed Bok Vincent canvas?

It would be unfair to give away the rest of the plot, but it can be disclosed that Peter is eventually accorded a painful yet liberating measure of self-knowledge. He is not, of course, a Rodin bronze. What vanity! If he is the work of any artist he is a Francis Bacon—“One of those pink fleshy middle-aged male nudes, in tortured repose.” He is neither artist nor muse but mere middleman, a servant and follower of art. “There are no gold-leaf stars painted on lapis over his head, just the gray of an unseasonably cool April afternoon.”

What Peter chooses to do with his new self-knowledge is the key to the book, the hidden canvas beneath Cunningham’s artful surface. By Nightfall is as full of James Joyce as The Hours is full of Virginia Woolf, but Cunningham is capable of creating fine literary architecture of his own, and the book has no need for Joycean scaffolding. Unlike Peter, he is an artist rather than a mere acolyte.