Populations Divided by More Than a River : AMERICAN OWNED LOVE by Robert Boswell; Alfred A. Knopf; $24, 352 pages

In a book reviewer’s life, it doesn’t get much better than this. I’ve just read a very good novel by a writer who’s not nearly as well-known as he ought to be--and a way of remedying that situation lies as close at hand as the computer keys I’m tapping on right now.

So listen up. The novel is called “American Owned Love.” The author’s name is Robert Boswell. He teaches at New Mexico State University and has written three other works of fiction--the novels “Mystery Ride” and “Crooked Hearts” and a collection of stories, “Living to Be 100”--which you’re advised to go ferret out at your nearest used bookstore.

Why is “American Owned Love” good? It’s tightly plotted--no detail goes to waste--but it also flows as loosely and unpredictably as life. Boswell’s prose never strains, but it’s capable of delicate and powerful effects. His people are so real that we’re reminded of what readers usually manage to ignore--that the characters in most novels are just bundles of stock attributes, snapped together like pieces of a Lego set.

“American Owned Love” describes the private motions of individual souls and, with equal ease, a place and a political situation. Persimmon, N.M., sits across the Rio Grande from the colonia, or squatters’ settlement, of Apuro. Apuro is 30 miles north of the border, but Persimmon’s residents behave as if it’s part of Mexico. They plant trees so they don’t have to look at Apuro’s adobe shacks, which lack sewer lines, electricity or running water. They refuse to build a footbridge, forcing the children of illegal immigrants to wade the river to attend school.

Rudy Salazar, the violent youth who is Apuro’s self-appointed avenger, notes that these kids are stigmatized as negras because of the dark line left on their pants even after the water dries. Watching the river literally run black one night--from toxic waste?--Rudy sees it as “a current of blood cutting its own wound.”

The black river means different things to others. To Gay Schaefer, it’s a symbol of the amplitude of possibilities; she can pursue Persimmon’s new basketball coach, Denny Redmon, while maintaining her unconventional long-distance relationship with her husband, Sander. Gay’s 15-year-old daughter, Rita, thinks her parents are divorced, but Gay, who has suffered breakdowns, sees her “careful, considered, artful arrangement” as the key to freedom and sanity.

To 14-year-old Enrique Calzado, the black river is mysterious and magical, like his father’s impending death from cancer and his own sexual awakening. Enrique’s upwardly mobile family left Apuro for Persimmon when he was a small child; his nostalgic longing for the shantytown mingles with his love for Rita (which he celebrates by dyeing his hair blond and, later, shaving it off). Sweet, goofy Enrique, whose fantasies threaten to intersect fatally with Rudy’s, is one of the most endearing kids American literature has produced.

Meanwhile, Persimmon’s self-important newspaper editor, Ron Morrison, agitates for Apuro to be bulldozed off the map. Gay’s spinster cousin Heart, who once lived with Gay and Sander on a commune, now has a curious relationship with a reclusive rancher, Mr. Gene. Unstable Claire Brownlee, whose detective husband knows everybody’s secrets, spreads malicious rumors about Gay because Gay, ducking out of a party to meet Denny, forgot she had promised to talk to Claire first. Rita comes to believe that she has healing powers; striving for purity, she develops anorexia.

But plot summaries tell us only so much. In a novel, everything important is in the details. It’s one thing to pick up a small town and shake it until all the dirty linen falls out of its hampers. It’s quite another to feel, as we do when reading “American Owned Love,” that the town is a greater rather than a lesser place the more we know about it; that even a brutal psychopath like Rudy, the deeper we look into him, becomes more human.

Now, it’s true that liking a book--liking it viscerally, getting bowled over by it--can make a reviewer unreliable. You might figure that grudging praise of a book I found temperamentally uncongenial might be better proof of its merit. And you know what? You’d be right.

Still, trust me on this one.