Phil Klay is enraptured by the nature of violence — by its persistence and its consequences, its dangers and its appeal. In “Redeployment” (2014), an award-winning collection of short stories concerning the experience of male soldiers serving in Iraq, he offered a distressingly intimate depiction of the ways in which wars deform the sensibilities of those who fight them.

Klay’s debut novel, “Missionaries,” returns to this theme, only here his concern is not the condition of Iraq and those who served there, but four individuals who are embroiled in the rampant savageries and shifting allegiances of war-torn Colombia.

Lisette, a disaffected American journalist who has been reporting on the war in Afghanistan, has recently found herself in Bógota to cover the region’s gang activity. Abel — who has been conscripted into a militia by a terrorist named Jefferson — spends his days squelching through the battles that are taking place between crime families and guerrillas operating in Colombia at the close of the 20th century, attempting as he does so to ensure the safety of the woman he loves.

Mason — a veteran, like Klay himself, of the Iraq war — is traveling to the area from the Middle East in order to participate in the ongoing struggle (which he regards as constituting a “good war”) against the region’s paramilitary narcos. And Juan, with whom Mason forms a friendship, is a principled and exhausted Colombian military officer who is striving to establish for his nation a deal that will bring an end to the decades of conflict by which it has been disfigured.

Introducing us to these characters by means of a series of alternating chapters, Klay goes on to show how their lives will come to be entwined. In doing so he demonstrates — often with great energy and insight — not just how the death and barbarism to which they are each exposed affects their respective personalities, but also, and less successfully, how projects of interventionism can exacerbate the difficulties that they have been mobilized to ameliorate.

As we join him in this enterprise, we are exposed to numerous visions of stomach-emptying brutality. Abel, for example, sees a local mayor get strapped to a piano and cut in half with a chain saw. But these moments seldom feel gratuitous, and usually carry a moral purpose that is reflected in the seriousness and the subtlety Klay brings to the events and ethical reckonings endured by his cast — most of whom, with the exception of Lisette, are depicted with precision, attentiveness and an ennobling capacity for imaginative compassion.

This is not to say that the book is without shortcomings. Klay has a habit of pursuing lengthy and tedious digressions. Large portions of his narrative feel polemical and clumsily politicized. And structurally, the book is somehow at once too messy (in its organization) and too neat (in its conclusion). These infelicities divest the novel of aesthetic force. But they do little to diminish the intensity of its apprehension of the horror — and the attraction — of the coarsening magnetism of violence.

Matthew Adams is a British writer and critic, working on a book about the cultural history of lighthouses.

Missionaries
By: Phil Klay.
Publisher: Penguin Press, 416 pages, $28.