Mortals by Norman Rush. Knopf. 713 pages.

As novelists go, Norman Rush came to writing - or at least publishing - rather late in life, which may be why he's never seemed like an amateur. His 1986 debut, the story collection Whites, published when he was well past 50, revealed a late bloomer who was not only practiced at his craft, but who had logged a lot of time in the real world - like serving as Peace Corps Director in Botswana for six years, among many other jobs - and had read widely. The stories, set among the white transplants and natives of apartheid-era Botswana, were works of chiseled subtlety that crackled with tension, wit and what T.S. Eliot called "felt life." The voices ranged from high to low, and each sounded utterly genuine; here was a country where a withering population uses any means to survive, the ruling class has every reason to be scared, and everyone feels trapped: by the heat, culture, politics. People at a disadvantage from dealing with each other wind up dealing with themselves, facing demons they'd rather not — like Carl, the American bureaucrat who decides that his hatred of his neighbor's barking dogs is symptomatic of his hatred of life in Africa. Rush immediately brought to mind masters like Forster and Conrad, for whom nothing quite so bares the Western soul as a terminal visit elsewhere. Like the great Bosch painting which has illustrated all the book covers of what now amounts to a loose trilogy, Rush's Botswana is a garden of earthly delights and the lushest hell on earth.

Good as it was, Whites was no preparation for what came next. Mating, Rush's first novel, was a ferociously intelligent love story and an extraordinary literary performance. Where Whites was sparing and contained, Mating was an explosion of verbal fireworks that dazzled from the first page to the last. The narrator is an unnamed anthropology student who recounts in random and meticulous detail her intellectual and romantic conquest of her academic hero, Nelson Denoon, a quirky theorist who establishes the female utopia of Tsau in the Kalahari Desert. Her goal is to absorb every speck of information she can; to not only be as close to Denoon as she can get, "inside the moat," as she puts it, but to be him, to soak his genius into herself. Her favorite word for their relationship is bolus, or "rounded mass," and that's what the book is; it swells from inward to out. Just as Tsau is a "guest organism superimposed on a large organism, the desert," so is she on Denoon; she wants to be remade by him and to remake him, to master all the kinks of his character that he can't master himself. It's a great, strange, exhilarating modern romance, and the voice that glides through it is brainy, vulnerable, and like none I've ever heard.