THUS far in his career, John Wray has received serious critical love. His first novel, "The Right Hand of Sleep" (2001), earned him a Whiting Award, a very pretty feather in any young novelist's cap. In 2007, two years after his second novel, "Canaan's Tongue," was published, Granta listed him among America's best novelists under 35. But admirers don't necessarily translate to an audience; neither of those complex, historical, darkly tinged novels brought flocks of casual readers. So, Wray still feels like a well-guarded secret.

It's impossible to predict what will capture the fancy of whatever remains of the reading public. But here is something certain: Wray's third novel, "Lowboy," is uncompromising, often gripping and generally excellent.

The book opens on a November morning, when 16-year-old William Heller enters the Manhattan subway system. Talking to an aged Sikh seated next to him, William explains he has a fondness for riding trains, specifically subways - hence his nickname, "Lowboy." His voice drops when he asks if the Sikh understands him. He checks over his shoulder to see if he's being followed. "The Sikh religion," he confides knowingly to the puzzled Sikh, "is less than 70 years old."

In sections that usually last less than a page, Wray deftly takes readers in and out of the psyche of what they will learn is a paranoid schizophrenic teenager, portraying Lowboy's unsteady viewpoint without sensationalizing or sugarcoating his troubles. Wray's sentences - though they occasionally elongate, turn rhythmic and zag - are mostly simple and declarative.

But their cumulative effect is to immerse the reader in a skewed perspective: the world reflected in a fun-house mirror, with places and people recognizable but distorted. Many of the novel's opening scenes contain sentences that, at first glance, are opaque; inevitably these sentences turn out to be seeds, waiting to open. Which is to say that while this book is easy to read, a small amount of patience is required before you really know what's going on.

But that's the beauty of it. One of the novel's many pleasures is just going along: putting yourself fully in the hands of its author, being drawn in, gradually immersed, making the connections, appreciating those seeds as they bloom into the tale's developing complexity, danger and tragedy. By the time it falls into place, the reader is long hooked and turning back is not an option.

I'd rather you experience this as I did, without many clues about what you're getting into. So, acknowledging the delicate border between book reviewer and plot spoiler, here's a skeleton: Lowboy is off his medication - which make him feel "like being pressed under glass" - and has just escaped his chaperones from a mental institution. He believes that global warming is going to destroy the world in 10 hours, that he's the only one who can stop it and that the fate of the planet hinges on whether he can partake in a certain preoccupation of most adolescents and adults. His mission brings him to Emily, a teenage hipster dream girl he used to date, who had something to do with the circumstances behind Lowboy's institutionalization.

Alternating with Lowboy's adventures are chapters following the detective Ali Lateef (given name Rufus White) - who has been charged with finding the missing boy - and Lowboy's mother, Violet, a beautiful, difficult woman with an accent of uncertain origins. Both want to find William. (Ali: "Why didn't you just ask the State of New York to hold on to your boy for another 18 months?" Violet: "I did.") But their motivations are different.

Ali is interested in stopping this kid before he hurts someone; Violet wants to find him before he hurts himself. Their scenes - alternately confrontational, adversarial, supportive and flirtatious, often within a matter of sentences - act as ballast to Lowboy's. These sections not only give the reader a grounded point of view but also fill in gaps about the boy's childhood in New York and provide perspective on his illness.

No small amount of "Lowboy" takes place underground, in subway cars and stations. Along with the smooth assimilation of a truly huge amount of information about subways, Wray's writing here is vivid: "Just then the uptown B arrived and saved him. Its ghost blew into the station first, a tunnel-shaped clot of air the exact length of the train behind it, hot from its own great compression and speed, whipping the litter up into a cloud." Moreover, when he turns his talents onto the streets of New York City and its boroughs, Wray reveals a poet's eye, sharply rendering a tray of cupcakes ("green and pink clots cupped in pleated wax paper"); the odd message on a nightshirt ("Flatbush is for lovers"); the innards of an old, shut-down station beneath City Hall ("tiles green as tidewater, yellow as teeth"). His New York is recognizably multicultural, at once current and timeless, and serves as an apt backdrop for Lowboy and Emily's jaunts, as well as Ali and Violet's chase.

All the characters here are vibrant, thinking and flawed, with their own sets of priorities. Usually they are a step ahead of the reader, which means you're constantly reading dialogue you didn't expect. This is a meticulously constructed novel, immensely satisfying in the perfect, precise beat of its plot. Wray, however, has larger goals than a thrill ride.

The book's core is a nexus of tragedy - the tragedy of a 17-year-old girl who, though she knows better, might do anything for the boy she loves; the tragedy of a mother whose life has been devoted to her son, yet who is incapable of helping him and who just may have been the source of his troubles; the tragedy of a middle-aged man caught between protecting the public and helping a parent; and finally, ultimately, the tragedy of a bright and beautiful teenager who not only must deal with all the confusions and pressures of being 16, but who, through no fault of his own, is not stable enough to be able to purchase a cupcake without confrontation.