Roberto Bolaño’s first fulllength novel translated into English, “The Savage Detectives” (Farrar, Straus & Giroux, 592 pages, $27), extends and vindicates the weird vision of his shorter volumes. Four of those works, translated by Chris Andrews and published by New Directions, have already appeared on our shores. In each, Mr. Bolaño imagines an international literary underworld, founded in rumor and obscurity, that evokes the passionate futility and complexity of postmodern youth, in Mr. Bolaño’s native Santiago, in Mexico City, and elsewhere.

The given, in each of Mr. Bolaño’s fictions, has been the importance of literary ephemera. The fragility of the written word, the lost book, and the unpublished poem have represented the shrinking and disappearing horizons of Mr. Bolaño’s characters.

They are like beat poets, searching for a search, or better, like European avant-garde artists, adjudicating their own clubby minutiae in the name of societywide reform.

Loosely autobiographical, “The Savage Detectives” features one Arturo Belano and his sidekick, Ulises Lima, who together found a group called the Visceral Realists and become absentee fathers to a generation of marginal Mexican poets. One of these, Juan García Madero narrates the first section of the novel. Madero is a pedantic neophyte, alive to cliquish drama. An orphan, he believes in the Visceral Realists, and follows Belano and Lima over a narrative cliff that ends the first section of the novel.

It is New Year’s Day, 1976, and the two poets leave Mexico City in a speeding Impala, escaping from an angry pimp. Then follows the long center of the novel, told in a choral form by various eyewitnesses and friends, few of whom appreciate the cult importance of the two youths. This part of the narration carries us through Barcelona, Paris, Israel, and Africa, between 1976 and 1996, and portrays a poetic commonweal of student flats, odd jobs, unwashed days, public baths, and sexual leapfrog. Some eyewitnesses believe in the romance of this life, some don’t.

In previous works, I worried that Mr. Bolaño could only keep up his bibliographic romance, with its undertow of dread, for the duration of a novella. But in the exhaustive reaches of “The Savage Detectives,” it becomes clear that the romance is meant to be limited. The real story, in Mr. Bolaño’s fiction, is the nerve of poets, electing to believe in one another’s genius. Before his early death in 2003 at the age of 50, Mr. Bolaño described “The Savage Detectives” as “a love letter to my generation.”

Despite all we learn about them, Arturo Belano and Ulises Lima remain shadowy figures — “like two extraterrestrials,” concludes one witness. To remember a young poet you once knew becomes a test of literary faith and a premonition of obscurity, and death. “Life makes us so fragile,” says Amadeo Salvatierra, one of the most important witnesses, “and some people, though this hasn’t happened to me, are even hypnotized or end up with the left hemisphere of their brains split down the middle, which is a figurative way of describing the problem of memory, if you follow me.” In a similar metaphor, another character describes how “suddenly my memory went plumph, like a soft wall collapsing, and I saw Horace fighting against Augustus or Octavian.”

The inability to remember a historical anecdote becomes, in Mr. Bolaño’s dense web of recollections, an expression of ultimate incompleteness. He sees Mexico City, in this mode, as a future ruin. “How sad everything he was telling us was,” notes one witness after another, about Belano, and his erratic, unproductive life.

The frank sadness of Mr. Bolaño’s vision is always cut with the grandiosity of doom. His instantaneous images, so assertive in their flickers of apocalypse, punctuate his otherwise talky prose. On a nighttime freeway, to take one example, García Madero sees passing semitrailers: “Each truck looked like a burned arm. For an instant there was only the noise of the trucks and the smell of charred flesh. Then the road was plunged into darkness again.” This is from the final section of the novel, the Sonoran desert adventure, a story of bullfighters and archives that sets the stage for Mr. Bolaño’s unfinished novel, “2666” (forthcoming in translation), introducing the fictional city of Santa Teresa, a city of assassins.

For Mr. Bolaño, belief in ragtag literature becomes a belief in apocryphal history, ignorant and powerful. Alhough the intimation of an exciting negative climax to world history pervades youth culture, no one but Mr. Bolaño has painted the sociological sadness behind this sentiment so convincingly. Entropy beats explosion every time.

blytal@nysun.com