“This is not a war run by idiots,” Sebastian Junger says. We’re sitting on lawn chairs in a shady red-brick courtyard on the UCLA campus, where Junger, 48, has just participated in a panel discussion about his new book, War, as part of the Los Angeles Times Festival of Books. Having been embedded with a U.S. Army platoon in 2007 and 2008 during its15-month deployment in Afghanistan’s Korengal Valley, Junger is explaining what most of us don’t know about the war in Afghanistan–or war in general. Among his points: soldiers on the ground don’t think about politics–they have a job to do; war is literally intoxicating, like a cocaine high; Hollywood doesn’t understand war, at all; and at the heart of combat is love.

That last point is the crux of both Junger’s book, which comes out today, and the documentary film he shot and directed with British filmmaker and photographer Tim Hetherington based on the Korengal experience. The film, Restrepo, was Junger’s first, and it won the Grand Jury Prize at Sundance in January. It was released Friday.

How does a first-time filmmaker win at Sundance? The same way he parlays his convalescence from a tree-cutting chainsaw accident in 1991 into a magazine article about one of the worst storms to ever hit the East Coast, which then becomes the best-selling book The Perfect Storm.

While Junger was laid up in Gloucester, Massachusetts, recovering from the tree injury, he got the idea to write a book about dangerous jobs. “I started getting interested in loggers, commercial fishing, fire fighting, foreign correspondents, oil well drilling. I picked out six jobs that didn’t involve guns, and that weren’t performance jobs,” he said in an interview at the time. Then, the storm hit near Gloucester and what started out as a potential chapter in a book became a book in itself.

Being nearly blown up in a Humvee, which he captured on film, was a turning point in his reporting. “I was like, fuck you. You’re not going to kill me,” Junger says.

After that, Junger became a celebrity adventure writer–and was even feted as the new Hemingway. He contributed adrenaline-filled stories on whale hunting and rock climbing to magazines like Outside and Men’s Journal. “Sebastian’s a phenomenal reporter,” says Restrepo co-director Hetherington, who also shared a Columbia-Dupont Award with Junger last year for a piece they did together on the Korengal Valley for Nightline. “He talks about so many things other journalists won’t talk about. There’s an honesty to him.”

In a sense, he’s now back to his original quest, this time writing about the far more serious job of soldiers. With War and Restrepo, Junger wanted to simply document what they go through, minus any political commentary. “What I wanted to know is, what are the emotional experiences of combat, stripped of all the macho bullshit we see in movies?” he says.

It wasn’t something he felt had been done successfully in Iraq or Afghanistan by journalists--himself included, in his previous stints as a war correspondent. He has spent most of the last decade as a contributing editor for Vanity Fair covering international conflicts, including torture and executions in Liberia, the civil war in Sierra Leone, and war crime atrocities in Kosovo.

The Korengal Valley was by far the most dangerous place Junger had ever been. While he was there, a fifth of all the fighting in Afghanistan was being waged in this six-mile-long valley near the Pakistan border. “I’d never been in this much actual combat,” he says. Two close calls–a bullet striking just inches from his face and an IED blowing up a Humvee he was riding in–made war feel personal to him for the first time.

The Humvee experience, which he captured on film, was a turning point in his reporting. “I was like, fuck you. You’re not going to kill me,” he says. “I had all these somewhat irrational anger responses and I started to understand how killing works. I don’t want to kill anybody, but I felt that impulse come up in me. And I’m not even carrying a gun, I’m just carrying a camera, but still, there it was.”

Junger’s writing about this transformation in War becomes a vehicle for understanding the soldiers’ mentality toward combat. These are young men, after all, who engage in outrageously dangerous, even suicidal, acts of bravery to protect each other.

Initially, he resisted personalizing the book. “I didn’t want to make me the star of the story. It’s about the soldiers, not my experience,” he says. “But then I realized my experience actually illuminated their story in interesting ways. And I had more access to it because I could examine my own feelings better than I could examine theirs.”

A decade ago, Junger says, he would not have departed from a strict journalistic style to be demonstrative about himself. “I’ve matured in a lot of ways in the past 10 years,” he told me, rubbing the salt-and-pepper stubble on his face. “I don’t think I would’ve been in touch with the emotional part of this book. I don’t think I would’ve been able to access it 10 years ago.”

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A former editor of Men's Journal, Claire Martin has written for Outside, the New York Times, and the Los Angeles Times magazine.