BOOK REVIEW : The Brutal, Degrading Poverty of Tijuana’s Borderlands : ACROSS THE WIRE, Life and Hard Times on the Mexican Border by Luis Alberto Urrea , photographs by John Lueders-Booth ; Anchor Books $9; 192 pages

Twenty minutes from downtown San Diego is the secret place that Luis Alberto Urrea calls “the Borderlands,” a festering nether world of orphanages and garbage dumps and “pig villages,” where the poorest of the poor from all over Latin America cling precariously to the underside of the Third World.

“Everything happens here on Saturday nights,” says one of the missionaries whose ministry is the Borderlands. “Anything you can imagine. Everything. “

Urrea leaves nothing to the imagination in the pages of “Across the Wire.” Indeed, he insists on writing with unflinching candor and raw clinical detail about the very worst manifestations of the disease, brutality and sexual degradation that afflict the men, women and children who live in the Borderlands. And if the reader is rendered sick at heart or sick to the stomach by the particulars of human misery, so be it.

“Poverty is personal: it smells and it shocks and it invades your space,” Urrea writes. “You come home dirty when you get too close to the poor.”

Urrea was born in Tijuana, the child of a Mexican father and an American mother, and his mastery of language helped earn him teaching appointments at Harvard and other American universities. Still, Urrea was drawn back to his birthplace, where he served as the translator for a charismatic Baptist missionary who showed Urrea a dimension of suffering that even a native knew nothing about.

“I thought I had escaped Tijuana for good, but I should have known,” Urrea writes. “Tijuana is the place form which you never get away.”

Urrea may have signed up as a missionary, but he brought to his calling all the visceral outrage of a social revolutionary and the lyrical impulses of a poet. And so, when he gazes at a landscape of heartbreaking and mind-numbing poverty, he is able to discern the peculiar social ironies that may escape the more casual observer.

For example, Urrea points out that even something so desolate as a garbage dump--a dompe , as it is known in the patois that Urrea calls “border-speak”--actually supports a teeming colony of trash-pickers who dig for secret treasure (a case of water-damaged Pampers is a gem beyond price) while living in an elaborate and almost-medieval social hierarchy.

“Some dompes even have ‘mayors’,” he writes. “Some have hired goons, paid off by shady syndicates, to keep the trash-pickers in line. It’s a kind of illegal serfdom, where the poor must pay a ransom to the rich to pick trash to survive.”

Sometimes Urrea’s obvious love of language prompts him to romanticize what he beholds, and his more florid moments tend to blunt the hard edge of his prose. At one point, for instance, Urrea pauses to remark on “a cigar that looked like an immense cocoon, the pupating grub of some noxious prehistoric insect”--but the point was lost on me.

More often, however, Urrea speaks to us in an unsentimental tone of voice that is no less evocative for being so sharp and so spare. A marriage of convenience between two barrio-dwellers, for example, is described in blunt but revealing terms: “Jose moved into Pacha’s bed,” Urrea writes. “It was a simple agreement, as firm as a wolf’s.”

“Across the Wire” is stitched together out of Urrea’s reportage for the San Diego Reader, but his book is a rare example of newspaper journalism that fully deserves to be preserved between book covers. Each chapter is a short take, not more than a column’s worth of prose, but it adds up to something greater than the sum of its parts--a work of investigative reporting that is also a bittersweet song of human anguish.

A terrible sense of futility surrounds the work of the missionaries whom Urrea describes. He buys a pair of shoes for a young girl named Negra so she can attend school; the very next day, she is set upon by hoodlums and the shoes are stolen. On his second visit, Urrea buys her another pair, but it is already too late; she has been expelled from school because she has missed too many classes. And when he visits her village again, Negra is gone and her shack has been turned into a whorehouse.

“That’s life,” as a crooked cop tells Urrea in another context. “What did you expect? This is Tijuana.”

But Urrea refuses to abandon the hope of redemption, no matter how remote it may seem, and so, curiously enough, “Across the Wire” is not a tale of unrelieved despair.

“Preach with your life” is the epigraph that opens the book, “not with your mouth.” And, when I put it down, I was haunted by the words of a woman from a still poorer province of Mexico who looks on the Borderlands as a kind of promised land.

“At least,” she says, “here you have garbage.”