JANUARY SUN <i> by Richard Stengel (Simon & Schuster: $19.95; 203 pp.) </i>

“One day, three lives, a South African town” is the poetic subtitle of this beautiful piece of journalism. Richard Stengel exposes the complex workings of apartheid through the dramatic device of following three lives during one day, dividing the action into morning, afternoon and evening. The location is Brits, a small community in the farmland of the western Transvaal, and the narrative moves among Brits’ segregated precincts as it traces the three characters: an Afrikaner, an Indian and a black.

The Afrikaner is Dr. Ronald de la Rey, a veterinarian who specializes in embryo transplants and artificial insemination. The practical vet has no trouble applying the rules of his practice to the human world: Genetic lines must be managed for greatest strength and purity. He is fiercely protective of the heritage of his ancestors in South Africa, and carefully cultivates in front of his house a perfect line of breadtrees, which nourished the early Afrikaners. Marshall Buys, known as Life, is a black taxi driver. A great part of his function in the black township is to carry messages between houses with no telephones. Jaiprakash (Jai) Bhula keeps a shop in the Indian township of Brits. His life is more comfortable than Life’s, yet he, too, is confined to the level of society where his color places him.

Through the details Stengel observes (from Life’s trousers, “the bottom half of a suit he never owned,” to political arguments over physical expansion of the segregated townships), he reveals more about the separate lives than he could with any amount of analysis. The three men’s position in the world, for instance, is mirrored in their access to the technology and conveniences of modern life. De la Rey, the man in power in this society, operates his neat laboratory and philosophizes about laziness and the virtue of work. Jai works hard and enjoys the fruits of his labor, consumer pleasures such as his VCR. But the black township is the junkyard for these conveniences, witness the ragtag fleet of cars that end up rusting outside Life’s door: “Taps (Life’s neighbor) can make even the most moribund engine turn over. He keeps all his parts in the courtyard and never throws anything out. The few cars in the township are pieced together from the part of others; when one car dies, its organs are transplanted into another.”

Stengel manages with such descriptions to indicate not only the poverty, but also the vitality, of the lowest rung on the social ladder. At the same time, he explains how the daily human economy of the apartheid system maintains its momentum, even as the struggle to overthrow it continues.