Unassigned Territory by Kem Nunn (Delacorte: $16.95; 312 pp.)

Kem Nunn’s first novel, “Tapping the Source,” an American Book Award nominee for 1984, looked almost like a new hybrid, the thriller as coming-of-age novel. A painfully stunted boy leaves the California desert and travels to the sea looking for his missing sister, only to find himself instead. The demands of a mystery gave the adolescent material an unusual urgency; and that almost autistic youth warily emerging into life was a true piece of ur-California.

Nunn’s new book concerns the worldly education of another innocent from that great inland empire, but this time the vision is comic and the journey is not West to the water, but North and East, deeper into the desert itself.

Nunn clearly loves the desert, not just the shimmering, colorless vistas and mind-crushing light, but the madness, violence, crackpottery, and perhaps even spiritual enlightenment it breeds. The landscape is more than a setting; it is the dominant force of the novel, dwarfing, tormenting and, finally, instructing the characters in its own strange wisdom.

“Unassigned Territory” follows Obadiah Wheeler, a young, guilt-ridden lay preacher in a harmless evangelical sect known as The Way. Weak of faith, but needing ministerial status to maintain his draft deferment (the year is 1968, a fact otherwise irrelevant to the story), he sets out with a few co-religionists on a missionary foray into the vast emptiness where California and Nevada meet.

Obadiah’s mind, however, is occupied more with the flesh than the spirit, at least in the early chapters, and before long, he’s ditched the Christians for a black-haired tart named Delandra Hummer. She no sooner relieves him of his virginity than he finds himself helping her rip off her late father’s Desert Museum of its chief attraction: The Mystery of the Mojave, a.k.a. The Thing, a humanoid sculpture the old man constructed (or found) just before he died.

Harlan Low, leader of the flock Obadiah has abandoned, goes looking for his lost sheep, encountering along the way the weirdly recurring image of a six-fingered hand. Delandra’s half-brother, Rex, thinking his paternal legacy has been stolen, packs up his Hum-a-Phone (through which one can listen to the music of the spheres) and takes off after the fleeing lovers.

Delandra, meanwhile, is trying to peddle the Thing to the Table Mountain people, followers of the late Ceton Verity who believed evil was a magnetic phenomenon that he could control with his Electro-Magnetron, which device, however, he never got working for lack of a single, crucial part. The Mountain people suspect that the Mystery of the Mojave has something to do with that part and/or with the extraterrestrial Verity prophesied would one day carry them off to a better part of the Universe.

Delandra is happy to feed these fantasies if it raises the price, though to her, the Thing is just junk. To the extent that “Unassigned Territory” has a theme, it occurs in the collision between pragmatic skeptics like Delandra, to whom “things” don’t speak (“The landscape offered no answers. But then it had never been much of a companion.”), and believers like Obadiah who look for messages everywhere: “. . . he wondered if there was not, somewhere in these acres of light, in the hieroglyphics at his feet, or even somehow, in the silence itself, an attempt to communicate.”

But the desert swallows themes and theories along with everything else. For all the echoes of Pynchon, an inland version of “The Crying of Lot 49,” the writing doesn’t have that precise paranoid detail or deep love of conspiracy theory. In fact, Nunn can’t seem to decide how seriously to take his characters and their obsessions; he wavers between empathy and scorn, though always with an odd indifference. Gone is the simple sincerity of “Tapping the Source,” replaced by a garrulous, arch bemusement: “For such a diminutive person, the girl proved herself capable of a horrendous amount of noise.”

Gone too is the clear, direct storytelling of the thriller. Nunn works up a few unnecessary subplots, then intercuts them in a way that coyly omits crucial narrative information and virtually all dramatic moments. The gaps are filled in imperfectly or not at all.

Yet the confusion and vagary are deliberate. Nunn is trying to produce the spacey effects of the desert, a world where knowledge dissolves in one’s hands. The novel is rigorous in its refusal to let the reader orient himself, and this discipline, the withholding of the usual pleasures and meanings, is ambitious and, at least in its intentions, admirable.

Unfortunately, it is sabotaged by what my high school English teacher called the fallacy of imitative form: the mistake of conveying confusion by confusing writing. “Unassigned Territory” is an infuriating and frustrating book precisely because having suspended the usual logic, nothing fills the void, no serenity, no divine contemplation, no ineffable mystery. We have only a story so murky, a pace so tedious that the mind finally gives up the effort of attention and, as in the desert, goes limp.

Nunn’s ability to induce this kind of literary sunstroke is a genuine tribute to his skills. The trouble is that we’re asked to lose our minds without being offered anything in their places.