In “Thank You,” Mr. Finkel writes that an estimated 20 to 30 percent of the two million Americans who fought in Iraq and Afghanistan suffer from post-traumatic stress disorder. Today’s war literature echoes with a sense of the emotional and psychological toll exacted on soldiers: the stress of multiple deployments in an overstretched military; the anxiety of working in chaotic conditions where it was difficult to distinguish between the people you were trying to protect and the people who were trying to blow you up; and where I.E.D.'s, sniper fire and roadside bombs turned daily patrols into a dangerous game of Russian roulette.

Capturing a War’s Rhythms

That rhythm of random, helter-skelter fighting interspersed with boring lulls is reflected in the jagged, staccato pulse of a lot of Iraq and Afghanistan writing: Short stories, authors have realized, are an ideal form for capturing the discontinuities of these wars, their episodic quality, and so are longer, fragmented narratives that jump-cut from scene to scene.

Instead of traditional battles and campaigns, there was often a terrible “Groundhog Day” quality to the fighting in Iraq as soldiers were charged with repeatedly taking and retaking streets and towns from the insurgents. Michael Pitre — a Marine who was deployed twice to Iraq — captured those absurdities in his novel, “Fives and Twenty-Fives,” by focusing on a road repair platoon’s dangerous but unglamorous assignment of clearing and filling potholes, 157 out of 157 of which contain some form of explosive device.

In his elegiac 2012 novel, “The Yellow Birds,” Kevin Powers took a different tack, turning the Sisyphean nature of war in Iraq into a kind of sad parable. “We’d go back into a city that had fought this battle yearly; a slow bloody parade in fall to mark the change of season,” writes Mr. Powers, who joined the Army when he was 17 and served as a machine-gunner in Iraq in 2004 and 2005. “We’d drive them out. We always had. We’d kill them. They’d shoot us and blow off our limbs and run into the hills and wadis, back into the alleys and dusty villages. Then they’d come back, and we’d start over by waving to them as they leaned against lampposts and unfurled green awnings while drinking tea in front of their shops. While we patrolled the streets, we’d throw candy to their children, with whom we’d fight in the fall a few more years from now.”

Image Michael Pitre in Iraq in 2007. His novel focuses on a road repair platoon in Iraq. Credit... Michael Pitre

Mr. Powers is also a published poet, and his novel has a haunting, lyrical feel to it, as does Brian Turner’s memoir, “My Life as a Foreign Country.” Mr. Turner, a seven-year Army veteran, has written two books of verse, and his writing often takes on a dreamlike mood reminiscent of Mr. O’Brien’s Vietnam novel, “Going After Cacciato.” But the phantasmagorical quality that has come to be associated with Vietnam in novels like Stephen Wright’s “Meditations in Green” and movies like Francis Ford Coppola’s “Apocalypse Now” seems relatively muted in Afghanistan and Iraq literature written by Americans.

Part of this is because literary innovations associated with earlier wars have long since trickled down into the culture at large and been absorbed into our jangled, aesthetic DNA: A modern sense of irony, Paul Fussell argued in his brilliant book “The Great War and Modern Memory,” was birthed in the horror of the trenches of World War I; black humor was used by Joseph Heller and Kurt Vonnegut to depict “the good war,” World War II; and Michael Herr employed a fragmented narrative, along with his singular electric language, to capture the Vietnam War on a synesthetic gut level.