Phil Klay graduated from Dartmouth College, in Hanover, N.H., in 2005. Afterward, he was commissioned as a second lieutenant in the Marine Corps and was deployed to Iraq from January 2007 to February 2008. Out of his experience in Iraq comes Redeployment, Klay’s raw, haunting debut collection of stories, published this month by Penguin Press. The author, who is now 30 years old, was born in White Plains, N.Y.

Klay began talking to Army recruiters during his sophomore year at Dartmouth. “It wasn’t a common move,” he admits. “But I thought, regardless of whether the war was right or wrong, how well we did would be measured in human lives. It felt like an important moment in history, and there was a chance for me to play a role.” There’s a tradition of public service in Klay’s family. His father was in the Peace Corps, his mother is the daughter of a career diplomat, one of his older brothers was a marine, and one of his younger brothers is in the Army Reserve. Klay has always been athletic, he says, boxing in college and playing rugby. In addition, he says, “I like the ethos of the military, and the idea of joining an institution in which, at the very least, everyone who signs up believes in something.”

When he joined the Marines, Klay’s family was understandably concerned, however; and several of his professors had strong feelings about his decision (one went so far as to tell him that the military is “the death of the mind”). Undaunted, Klay did six months of general training before shipping out—“You learn a lot about yourself,” he says. “It’s your entry into the duties you’re going to have as an officer. You get to see different styles of leadership, and you start to think about things in a very real way.”

Klay studied English and creative writing in college, and was an avid reader, but he didn’t consider “being a writer.” He knew he wanted to do something that involved writing, and says that working as a public affairs officer in the Marine Corps filled that desire in many ways. “It was a very odd job to have in the military,” he explains. “You interact with the media, you have a group of marines working for you writing stories and taking photographs, and I ended up spending a lot of time with a lot of different units.” Klay went to patrol meetings with Iraqi police, sat in on generals’ meetings, spent time with medics and engineers, dealt with the civilian press, and communicated with marine families back home.

The stories in Redeployment vividly portray the horrors of war—the violence and brutality—but Klay says his job wasn’t particularly frightening or intense: “It was abstract to me—you would hear a boom on our base, and then nothing for a week or a month. It was the surge, so the violence was dialed down.” But despite this assessment, you can sense something in his demeanor—that he’s seen things, been affected by them, and that his stories tell this truth.

Much of Redeployment focuses on soldiers returning home and the difficulties they face reentering society. Klay can speak to this frankly and honestly. He describes taking a trip to New York City while on leave during his service—“I literally went straight to New York City from Iraq, which was bizarre, and complicated. I was walking down Madison Avenue and it was spring, and people were smartly dressed, and it was so strange because there was no sense that we were at war. It was something to grapple with.”

After 13 months in Iraq, Klay came home. He left the Marine Corps in July 2009 and got his M.F.A. from Hunter College in New York. “For me, leaving the Marine Corps was more disorienting than returning home,” Klay says. “I came back from Iraq with all of these experiences that stayed in my mind that were troubling—conversations I’d had that don’t fit into the conventions of talking about war.” Klay also found it difficult to be around civilians after being surrounded by Marines for so long. “People have expectations about what your return means, and there are dominant modes for thinking about war experiences and what those experiences mean—and they’re not sufficient,” he says. He used his writing to deal with these incredibly complex feelings. “Writing is the best way that I know to think about something, because you put it down, and you put it under pressure, and you examine this idea that you have.”

Klay sent his work out to a lot of different people. “I feel like people lie to themselves all the time about their own experiences—about what they were and what they meant. But that stuff ends up really thin when you put it into a story, into writing. So I took in what people said about my work; I wrote and rewrote. That was my process.” The book was difficult to write, he says, and he’s not certain that it was therapeutic. “Some of it is upsetting, some of it is enraging.”

Klay worked on the book for four years, doing extensive research. “My general thought was that in order to say what I had to say, I had to make myself an expert.” He wrote the book’s title story first—in 2008, while he was still serving—and finished the collection in January 2013. The brutality that Klay presents is evident from the very beginning of that first story: “We shot dogs. Not by accident. We did it on purpose, and we called it Operation Scooby.”

The process of writing the book, Klay says, changed the way he thought about things. “I started out wanting to chase down some of these things that troubled or confused or interested me—and I wanted to understand more of the experience of the people whom I served with,” he says. He notes that he also wanted to think about what Iraq meant to America. Did it work? “I’ve certainly thought a lot more about things like tyranny and patriotism and violence,” the author admits. “I think I found some kind of clarity—definitely a thicker understanding.”

Who is Klay writing for? “I want a civilian reader to be able to read the book and think about it and engage with the subject matter, and I want veterans to be able to do the same,” he says. While he was deployed, he read Don Quixote, Gravity’s Rainbow, and the first three books of Anthony Powell’s 12-book triology, Dance to the Music of Time.

When asked if he thinks war has to be experienced firsthand to be fully understood, Klay responds immediately: “I think that’s a dangerous idea. Certainly it can be hard for someone to understand, but I don’t think that someone who has been through an intense experience, whatever it is, has privileged access to some kind of ineffable truth that cannot be spoken. Often we think just because someone has been through an experience means that he or she gets to be the arbiter of what it means. When we say that about a veteran’s experience, it seems like it’s privileging that person, but it also shuts him or her down. It gets the listener off the hook from having to understand, and it lets the veteran off the hook from having to explain.”

Klay acknowledges that the experience of war is a tremendously painful thing to share, and says that this book “is part of my attempt.” He wants his readers to grapple with the issues he brings to light. “It takes time to relate, and a certain amount of willingness, because maybe you don’t want to open that thing up to another person who is going to, in his or her interaction with you, change your understanding of what it is. It can feel like you don’t own it anymore if you share it.”

Klay says his next book will be about something other than war. “One of the things I like about writing is that you chase down these things that you think are important and vital, and then, after you’ve done that, you want to do something new.” For now, he won’t say what that next project will be.

Klay has been fascinated by readers’ and critics’ responses Redeployment. His initial plan was to read his reviews, both good and bad—but so far they’ve all been stellar. “Maybe it’s having gone through military training, where people scream in your face. Heinous reviews are amusing to me.” Klay says all he really wants is critical engagement with the book.