Roberto Bolaño is a master of digression. Among the countless stories that he tells in 2666, his 900-page cinderblock of a novel, there is not one that feels incomplete. (Considering that Bolaño died in 2003 before he finished the final book of the five-part sequence, that?s quite a feat.) In his hands, narrative tangents, followed to their logical (or illogical, as the case may be) conclusions, fill in the spaces opened up by the boundlessly layered story lines.

To call 2666 ambitious is to understate its scale. Comprising five almost autonomous books, the novel is a chronicle of the 20th century, unafraid to confront its more gruesome turns in its sweep across history. The binding link, insofar as there is one, is the Mexican border town of Santa Teresa, modeled on Ciudad Juárez, where for the better part of the 1990s there were hundreds of brutal murders, with the bodies of young women turning up in dumps and deserts at the city?s margin. The fourth, and longest, of the books takes up the matter of the murders directly, taking readers sequentially through each of the killings, along with the sexual abuse, mutilation, and police incompetence that accompanied them. They vary in their specifics, but the broad template is the same. “In September, the body of Ana Muñoz Sanjuán was found behind some trash cans on Calle Javier Paredes, between Colonia Félix Gómez and Colonia Centro. The body was completely naked and showed evidence of strangulation and rape, which would later be confirmed by the medical examiner,” Bolaño writes with the blank neutrality of a police report.

He treads a difficult line in his account of the murders, explicit in his brutality without letting his descriptions slip into the exploitative. In each case, he is matter-of-fact, but the sheer accumulation of grisly detail can be difficult to stomach. For the most part, the crimes remain unsolved, and in the instances that the police do track down the killer, it turns out not to be the sought-after serial murderer but another case of domestic violence in this grim, industrial borderland. These murders, for Bolaño, contain all the violence of Latin America?s colonial legacy, and the willingness of its witnesses to lay aside their own horror. Bolaño is at once oblique and microscopically precise in laying his themes on the table.

With Santa Teresa as a loose backdrop, 2666 radiates outward in all directions. The first book traces four obsessive European academics as their quest to find Archimboldi, the hermetic novelist at the center of their scholarly enterprise, leads them to Mexico. The second picks up with Amalfitano, a melancholic scholar whom they meet in their travels, as he begins to lose hold of his sanity, while the third, and in a way the most isolated part, tracks Harlem-based journalist Oscar Fate as he covers a boxing match in Santa Teresa. And finally the fifth, after “The Part About the Crimes,” returns to Archimboldi.

Bolaño, with 2666, seems to have taken up the banner of postmodern genre pastiche: his account of Archimboldi?s journey from rural Prussia to the Eastern Front of WWII to literary fame has all the trappings of the traditional bildungsroman, while the Oscar Fate section fits squarely alongside the gruffly laconic noir of American pulp. What separates Bolaño?s efforts to catalogue the 20th century in letters is the utter authenticity of his effort; it never feels as if he is playing mimic. Or as Amalfitano would have it, literature is at its best when it doesn?t suppress its own anarchy, “when the great masters struggle against that something, that something that terrifies us all, that something that cows us and spurs us on, amid blood and mortal wounds and stench.” Bolaño would seem to agree.

As in The Savage Detectives, Bolaño?s much-acclaimed novel of last year, the question of how life comes to bear on writing, and writing on life, is never far from the author?s reach. Like the visceral realist poets of that novel, 2666?s quartet of critics — Pelletier, Espinoza, Norton, and Morini — structure their entire existence around the pursuit of a phantom author. The mysterious Archimboldi, in turn, becomes immersed in the literary life almost by accident, clinging to the notebook of a Ukrainian poet that he finds by chance in the village where his unit is seeking shelter. For Archimboldi, Ansky?s words are consuming, a lifeline amidst the hopelessness of war: “He no longer thought about suicide, because he was already dead. In the mornings the first thing he did was read Ansky?s notebook, opening it at random.” For the authors among Bolaño ?s cast, the imaginative possibilities of literature lend structure to an existence that seems otherwise without it — the very texture of life is reflected in the mode of its telling.

But more than the fixation on the literary life shared by the characters of 2666, what ties the novel together is the predominance of an unimaginable violence. The murders in Santa Teresa are Bolaño ?s avenue into a century defined by the scope of the damage it wrought. What Archimboldi witnesses on the battlefield and channels into art is no better or worse than the savagery dispassionately reported by the Mexican police. In one of the novel?s most unsettling scenes, he encounters a corps of Romanian deserters who have killed and crucified their own general. “He wasn?t a bad sort,” one of the Romanians observes of his commander, the arbitrariness of their cruelty even more stark. And then there are the smaller brutalities. The distinction between sex and violence, as envisioned by Bolaño, can be troublingly porous, and the predation inherent in the Santa Teresa crimes casts its pall over the novel?s sexual politics. Even in the comparatively airy first section, the romantic entanglements of the four scholars take on a twinge of the sinister when Pelletier and Espinoza find a sexual rival in a friend of Liz Norton?s (with whom both, alternately, are sleeping).

The topography of violence may be what connects the disparate pieces of Bolaño?s rangy novel, but that does not mean — lest this seem too bleak to be readable — that there is no beauty in its midst. His prose, even as it flits across genres, never loses its undercurrent of humanity; his characters are never hollow vessels for his thematic aims. As Liz Norton muses, “For her, reading was linked to pleasure, not to knowledge or enigmas or constructions or verbal labyrinths?” In 2666, however, we get both: there is brilliance in its mystery, and in all the surprising ways that its manifold layers become whole.