It’s Doggy-Dog Along the Rio Grande : RAINBOW’S END<i> by Genaro Gonzalez (Arte Publico Press: $8.50, paper; 227 pp.) </i>

In the western stretch of the U.S.-Mexico border, the cities are more populated and the industries more sophisticated than they are at the opposite end. There, generations of social and commercial stagnation have brought on a very different life. In his first novel, Genaro Gonzalez gives us an intimate look at one typical South Texas family, from the old man who swam across the Rio Grande in the 1930s to his children and grandchildren who include Vietnam vets and smugglers.

The family patriarch, Heraclio Cavazos, is warm, possessed of insufferable integrity, and moral to a fault. These qualities gain him the respect and exasperation of family and friends alike; that author Gonzalez has so well integrated the verities of such a life into “Rainbow’s End” speaks well for the authority of his voice and the authenticity of its echo.

Cavazos lives his early years in a ramshackle house among companeros named Rooster, Tomcat and Greased Pig. He marries Chaca, whose death a few years later leaves him with two kids her family helps him raise, and we settle into the rhythms of daily life.

One wonderfully comic scene has a localized version in every Mexican-American barrio throughout the Southwest: The devil, a dapper dresser and seductive dancer, appears at a local dance, identified by a hoof at the end of one leg and a rooster’s foot on the other. Rumors spread wildly the next week in fearful anticipation of his return the following Saturday night.

When Heraclio and others go north to work the fields one year, the farm owner bamboozles them in the end. “Anytime it’s us against the gringos,” Heraclio’s son-in-law says, “you know who gets the breaks. So let’s stop being us and start being them.” “And lose our pride?” Heraclio responds. “Pride?” says Gilberto. “What’s that? Can you eat it? Can you at least grow crops in it? No . . . like the gringos say, it’s a doggy-dog world.”

The most poignant and comical scenes come when an elderly Heraclio, stubborn and doddering, is taken to a modern shopping mall to replace his sweaty and tattered hat. The same reluctance pervades his agreement to seek U.S. citizenship. “Who discovered America?” an immigration official asks. “Los indios,” Don Heraclio replies defiantly--the Indians--whereupon the sympathetic bureaucrat enthusiastically awards him citizenship.

Gonzalez has a playful way with language; his bilingual puns enrich “Rainbow’s End.” Difficulties come near the beginning with erratic jumps in time, and at the very end when he has trouble bringing his fine novel to a natural close. Between those problems, though, Gonzalez’s writing matures with his hero, and “Rainbow’s End” captures the ambiente of the life of a borderland household as well as any book I’ve read.