Indeed, it almost defines the difference between scholarly and academic writing. Scholarly writing, like his, is erudite and expansive in its range of reference and knowledge, but it is addressed not just to a nonexpert audience but to a larger humane mission. Laqueur wants to tell us why dogs matter, demystifying his subject while respecting its mystique. Academic writing, by contrast, besides being written for an in-group, often uses its erudition to assert superior understanding, telling us our belief that dogs matter owes less to real affection than to learned affectation. The purely academic version of the same book would be titled “Imaginary Friends: Constructing the Canine, 1200-2000.”

Laqueur begins, bracingly, with his own story: he grew up in a German Jewish family in which dogs were regarded as ornamental rather than beloved. Richard Avedon used to tell a similar tale, which Laqueur cites, of how his Jewish family in New York borrowed dogs for family portraits, though they would never have kept one in the house. Laqueur defied that tradition, owning and loving a succession of dogs, and from that fact he moves sideways to another, stranger one: as part of the Zionist “grounding” of the Jews, the “Canaan dog” was bred and retroactively installed as Israel’s national dog—truly, the invention of tradition on a leash.

He then returns us to an achingly familiar relic of our long entanglement with dogs: the preserved parallel footprints, in the Chauvet cave, in France, of a canid and a child, perhaps eight or ten years old. (The tracks can be seen in Werner Herzog’s fine film “Cave of Forgotten Dreams.”) Laqueur adds to this a bit of recent deduction. Given that the double tracks, dating back about twenty-five thousand years, seem most marked within viewing distance of animal pictures drawn on the cave walls, the child and the dog appear to have been walking into the depths of the cave together to stare at much earlier drawings of a late-Paleolithic horse.

And then, having established the timelessness of the shared companionship, rooted in the dog’s ability to “see us” in every sense, Laqueur’s erudition leads him to jump not to Charles Darwin, the student of animal emotion, but, more surprisingly, to Adam Smith’s theory of social sympathy. The dog is, so to speak, a freeloader on our belief in sympathetic exchange. It is party to a social contract that is interpreted differently by those who sign and those who offer it. Our dogs have no idea what society they live within, no idea that this is “New York.” Their idea of society is of street smells and habitual turns and familiar faces, and this limited awareness on their part reminds us that we, too, doubtless see our place in the universe incompletely, in ways that would be obvious to a higher order of intelligence than our own, one for whom cosmic space-time would be not a difficult concept but a felt reality.

There is a case to be made that the dog’s gaze is a kind of con game dogs play on us. They are creatures of the nose, above all, olfactory rather than optical in their primary apprehensions. Yet in the course of our coevolution their eyes have come to mimic human eyes. Dogs possess a distinctive trait that allows them to raise their eyebrows in imitation of human expression and to expose the whites of their eyes to us. “Seeing together and seeing one another is the basis of our co-evolution,” Laqueur writes. In one sense, this is an illusion, a sleight of eye, like the way we find the chubby cheeks of squirrels to be cute because they put us in mind of human babies. But the squirrels’ cheeks just lucked out. Dogs’ eyes evolved under selective pressure so that they would seem to look at us the way we look at them.

Laqueur takes the reader on a nearly encyclopedic trip through this truth and its consequences, ranging from Giotto’s dogs—calm, disengaged witnesses to holy stories (“At a foundational moment of Western art,” he says, “there is the dog doing what dogs do”)—to Bruegel the Elder’s massed and happy hunting hounds in winter, whose barks we can almost hear penetrating the bitter cold, and to Degas’s chin-lifted greyhound crossing the Place de la Concorde, as alienated as an urban dandy. Laqueur also has something rare, though essential to real scholarship, and that is taste. When he says, in effect, “Good dog!,” he’s right. He recognizes, for instance, that, in the late Quattrocento and beyond, the painters of Venice are the most sensitive to his subject. That might seem surprising for a maritime city where no one could hunt or chase wild animals. But perhaps this is part of the explanation: when dogs are not mainly servants, they can be seen more readily as subjects.

Several pages of “The Dog’s Gaze” are devoted to the most memorable little dog in art, the one in Carpaccio’s late-Quattrocento painting of St. Augustine in his beautiful Venetian study. The Maltese—who watches his master as the translucent apparition of St. Jerome appears at his study window—is alert and attentive without being capable of complete apprehension. We are reminded of dogs as an intermediary between mankind and the rest of creation, both sublunary and celestial; dogs remind us daily of our animal selves and are audience to our higher moments. Laqueur ignores, though, a small but significant fact in this scene: the Maltese is facing, directly across it in the tiny Venetian chapel where the picture lives, an image of St. George defeating a dragon, and the path from dragon to dog is surely the implicit subject of the chapel’s iconography. The good life is a procession from the dragon who lives within us to the dog who barks beside us.

Among the Venetians who came after Carpaccio, Titian, too, gets his due in “The Dog’s Gaze,” while Veronese, whom Kenneth Clark considered the greatest dog-lover of the Renaissance, enters in the episode in which, having placed dogs alongside dwarfs and clowns in his “Last Supper,” he was summoned by the Inquisition and forced to explain himself. Though Laqueur insists that this was not “a Galileo moment,” it was still charged: the presence of dogs made for a vulgar atmosphere in a divine setting. Significantly, Veronese did not argue, as a contemporary art historian might on his behalf, that dogs were symbols of fidelity or faith. He admitted that they were just dogs being doggy, then shrugged and changed the painting’s name from “The Last Supper” to “The Feast in the House of Levi,” an obscure incident in the Gospel of Luke but one genre-like enough to pass as a mere scene of everyday life. (Though, as Veronese perhaps knew, this is the episode where Jesus defends his dining with publicans and sinners, which might justify the mixed company in the painting.)

Dogs in Renaissance art are faithful but not divine. Their symbolic role is usually secondary to their real presence. Laqueur points out a disturbing, unforgettable instance of this in Titian’s “Flaying of Marsyas”: as Apollo skins the satyr alive for challenging him to a music contest and then losing it, a small dog eagerly laps up the spilled blood. The enduring animalness of the dog (Lucian Freud called it “animal pragmatism,” explaining why he wanted his people to resemble dogs) is one reason that the species can never be simply inducted into piety.

Indeed, there are aspects of a dog’s existence which resist crossing over into art. An inordinate amount of the time we spend with our dogs deals with defecation. We become as acclimated to their moods and needs in this direction as we are to our own. We even spend, in New York, much of our days with small plastic bags in hand, in a beautiful demonstration, which Adam Smith would have loved, of the delicate dance of both social obligation (there’s a law!) and social sympathy (no one enforces the law but the participants in the practice it governs). The exception to this pattern of absence seems to be Rembrandt, whose etching “The Good Samaritan” includes a large, defecating hound. The Met’s catalogue says that this is just a vulgar detail, but one suspects a poetic purpose here as well. The pragmatic dog is true to its nature and does not care about doing what it does where it does it. The man in the etching, the Good Samaritan, can transcend his nature, his inherent tribalism, and offer loving aid to one not of his own kind. (Or, perhaps, the Samaritan is following his true inner nature, the call to be kind, as the dog is answering its own call of nature?)

In the art history of the twentieth century, Laqueur is responsive to Matisse’s dogs. We seldom think of Matisse as a painter of dogs, but Laqueur is quite right that the artist has created some of the most charming images of them. The discussion occurs within a more tangled argument about the representation of dogs, beginning with Dürer, as symbols of melancholia. And, indeed, Matisse’s dogs, like Dürer’s, are often withdrawn, curled up asleep. But Laqueur sees that this Matissean melancholy is of a peculiarly happy kind. For instance, the dog sleeping beneath a blossoming magnolia branch in “Interior with Dog,” from 1933, resembles not so much Giotto’s watching dogs as the sleeping patriarchs they watch, Joseph and Joachim, content to withdraw into the circle of their slumber as glory goes on around them. Dogs can sleep through it all and delight us as they do. (There is also the strange affinity between Matisse’s dogs and those of The New Yorker’s James Thurber, both drawn in deliberately childlike outline, though Thurber was naïve by nature and Matisse by choice.)

Laqueur’s book has no particular thesis to hobbyhorse for, and yet a unified-field theory of aesthetic dogginess might be distilled from its pages. Dogs live within a neat symbolic divide. On the one hand, they represent courage, an intrepid readiness to take risks on behalf of their beloved; on the other, they represent loyalty, a refusal to be removed from the presence of their families. The dog in art both walks ahead with the hunters and stays behind with the gatherers.

These two things are not necessarily reciprocal. Brave men and women are often loners; loyal people are often timid homebodies. Dogs are both. To be both courageous and clingy is their unique moral charm. Even the smallest dogs will bark ferociously at the apparent entrance of an intruder, not calculating the odds but obeying their inbred sense of duty.

And within this reality lies a stranger one. Dogs are moral creatures without anything like moral volition. They are themselves representations. They are little poems we have written over generations on the themes of love and loyalty, courage and caution. We have bred them to inhabit and exhibit emotions, even contradictory ones, that we admire. They are loving because the ones who were less loving, more skeptical of the deal, were not allowed to have as many puppies as the ones who sprang at it, and they are daring because those judged too skittish were not allowed to have as many puppies as the ones who charged at enemies. We overwrote the wolf genome with our own dreams. Dogs impersonate virtues because they’ve been bred to, and turning our intuitions into their instincts is a kind of magic trick we play on one another.

Sometimes our poems on the themes of ferocity and fearlessness can be cruel to the dogs who must enact them. We have bred the pit bull and the mastiff to express our aggression and rage. Yet there is no love greater than that of the pit-bull owner for the rescued pit, exactly because the other side of the wolf, pack loyalty and a desire for love, can emerge so readily. For at the same time as we delight in dogs, somewhere deep down we recognize how precarious that construction is. If our dog went feral, as the majority of dogs on the planet already are, its exquisite balance of courage and camaraderie would be ripped apart, and desperate for food, as most animals on the planet are, it would, like its cousins the jackals, scavenge even dead human bodies. Indeed, there is a scary but well-established truth: even a beloved household pet will eat our remains if left alone with our lifeless bodies. That is something our children, in similar circumstances, would not do. Or so we hope.

Dogs embody both the ferocity of instinct and its fragility. The dog will do what its genome tells it to do, and its genome can be remade to have it do things it would not have thought of doing. Dogs teach us about empathy, joy, and unconditional love, but they do so because we have taught them to teach us. It is this double life of dogs, as unreasoning creatures governed by instinct and as moral exemplars practicing virtue, which makes us love them, and which comes alive in art.

Laqueur tells us that his own dog, beside him as he composed most of “The Dog’s Gaze,” died before its completion. Yet he leaves out the gaze that our dogs turn on us at the end, the one that for many is the most haunting of all. Doubtless, we project attributes onto dogs—sociability, altruism, compassion—which are of a higher order than they can regularly possess. But the trust we see in their gaze (I’m safe here, I’ll be fed, you won’t ever hurt me) is all the more powerful because it is so real. And because that trust is the other side of fear—the other universal animal emotion that we share—violating it, even for their own good so that they will not end their lives afraid and in pain, feels like a profound betrayal.

Two years after losing Butterscotch, we got another sand-colored Havanese, all but indistinguishable from her predecessor, or so our amused neighbors insisted. But Rosie—introverted, suspicious of strangers, not flirtatious but deeply loving, checking on everyone like a night nurse before going to sleep herself, not promiscuously social but trusting of a handful of people and other dogs—is an utterly new being, complete unto herself. When we share a poached egg on a coffee-shop terrace, she doesn’t beg for more, as her predecessor did, but looks up with almost unbearable tenderness: Thank you. The animal avatar of my wife, her chief friend, Rosie is delicate, elegant, and pretty. “She has human eyes,” more than one passerby in the park has marvelled. She does. Her eyes see everything but the inevitable, essential thing. One day, they will, as we both know and somehow can’t imagine. ♦