Writing in the Irish Times last February, the novelist Joseph O’Connor raved about the “exhilarating strangeness” of Sara Baume’s novel, Spill Simmer Falter Wither. “It’s hard to imagine a more exciting debut novel being published this year,” he announced. “This book is a stunning and wonderful achievement by a writer touched by greatness.”

With British critics swooning too, you might well think it’s time for an American backlash—but the book, now out in the U.S., is indeed an unsettling literary surprise of the best sort. This first novel’s voice is singular in its humility and imaginative range.

Baume (who is also a graphic artist) proceeds like a collagist, but here are the basics. Ray, the narrator, is a 57-year-old man who lives alone in a coastal Irish village in what he still thinks of as “my father’s house.” His father is dead, a sausage segment having “stoppered his windpipe” at breakfast one morning several years earlier. But he remains very much a presence in the otherwise solitary life of his son. Ray wears his father’s ill-fitting slippers around the house; he hangs two towels in the bathroom.

The father, readers discern, was a rather absent presence (or worse) during his life as well. He spent his days working in a factory Ray never saw and, by keeping mostly quiet on the matter, led Ray to believe that his mother’s death was linked to his birth—in other words, that he was guilty of doing inadvertent harm to others from the get-go. Because his father thought Ray “wasn’t a right-minded little boy … wasn’t all there,” he never sent his son to school. The late-middle-aged Ray whom readers encounter in these pages has had lots of practice feeling like a pariah, and decades of social exile have taken their toll. He’s stopped going to church and keeps to himself amidst his mountains of books (“spines and spines and spines, raised to towers on the coffee table, queued into rows along the skirting boards”). He goes into town once a week, briefly, to run essential errands.

It is only when Ray impulsively adopts a grisly, one-eyed dog that he’s able to see his life more clearly for what it is, only then that he dares push beyond its unspoken boundaries. After One Eye (as Ray names him) attacks another dog, the two misfits flee. They embark on a rambling car trip culminating, predictably, in a kind of catharsis. Man rescues dog; dog rescues man. Cue the violins.

The plot isn’t the novel’s claim to originality. What gives Baume’s book its startling power—despite several (or more, depending on your tolerance) near-misses with sentimentality—is her portrait of an unexpectedly protean mind at work. This isolate, it turns out, isn’t trapped in himself. He’s attuned to others in a thoroughly unusual way.

“Don’t you ever wonder,” Ray asks One Eye, “what exactly people do, all day long, every day?” Ray is constantly wondering, not just about people but also about birds and badgers and river creatures, and, of course, about the dog. He asks One Eye, with genuine curiosity, what the dog thinks of classical music. “You seem to be listening,” he observes, “but I can’t be sure.” Baume uses the second person so much that at times the “you” ceases to be the dog and becomes you, the reader, collapsing the distance between story and life. And yet by reinforcing the subjectivity of “you” as distinct from that of “I,” she underscores the solitary essence of Ray’s way of being; it’s the very existence of so many unknowable yous that makes his I so painfully lonely.

Shut off from the world, Ray has had to school himself on its workings, an endeavor that has made him more incessantly aware of the limits and possibilities of subjective experience than most people could ever manage to be. He doesn’t, perhaps can’t, simply take for granted the truth that every mind registers experience differently. For him, that idea is always in the foreground. Dogs can see only certain colors and understand only a couple hundred words. Badgers keep trying to cross the road the way they always have, even though they keep winding up “dead as the dirt they’ve been splattered by.” Ray says he’s “always noticed the smallest, quietest things,” but that’s only the start. It is a hard-won habit of his to also remember to wonder about all that he does not notice—beginning with the fact that, even in the lives of others, even when he can’t see it, “everything just goes on and on and on. Regardless, relentless.”

In fact, Ray depends on his awareness of those other minds—even if he can’t quite parse the meanings of what they say, or see things as they do—for his very survival. “The outer noises,” he says, “are important to me. It doesn’t matter what form they take or how loud they are, but I need to keep them always sounding.”

The result is that his world, blinkered though it may look from the outside, is anything but. A diagnostic term like Asperger’s syndrome may well flit into readers’ minds, but would never make it into the prose of the novel, which explodes conventional notions of textbook symptoms. In many ways, Baume’s book resembles another debut novel, Mark Haddon’s The Curious Incident of the Dog in the Night-Time (2003). Like Ray, Haddon’s protagonist has a single father who’s concealed crucial details of his mother’s death from his son. The unexpected intervention of an unassuming dog helps both characters find their way to a better understanding of their families and themselves. But where Curious Incident takes its narrative cues from a logical, rule-bound perspective on an overwhelming reality, Spill Simmer Falter Wither does the opposite. Baume’s novel revels in aesthetic leaps and dives, embracing the poetry of sensory experience in all its baffling beauty from the title onward.

Curious Incident, which starts with a dead dog, is about a boy on a solo journey toward maturity. This novel draws its strength from One Eye’s unpredictable, spirited aliveness, the physical proof that each creature harbors perceptive abilities all his own. With his “maggot nose” and that missing eye, he is a testament to the concealed depths—mostly ignored—beneath every surface. Baume’s prose makes sure we look and listen. Her book insists we take notice.