I had the good fortune of meeting Sebastian Junger a few years ago in Boston as he did the press junket for his book War. From mid-2007 to mid-2008 Junger was embedded with a U.S. unit in the Korengal Valley in Afghanistan with his friend and photographer Tim Hetherington, and War was one of the many pieces of journalism that resulted from that year. Another was a series of Vanity Fair dispatches collected as “Into the Valley of Death“, which is an excellent companion to War and an excellent account of that year in the Korengal. But the most affecting portrait from Junger’s tour as a war journalist might be Restrepo, the documentary he and Hetherington directed from the thousands of hours of footage they took during the year and ensuing interviews with the soldiers immediately upon their return home.

The Korengal Valley (sometimes spelled Korangal) was at the time dubbed the deadliest place in the world, an overblown-sounding moniker that is nonetheless entirely lacking exaggeration. U.S. troops in the Korengal took fire from Taliban insurgencies every single day, often engaging in five or six firefights between dawn and dusk. For soldiers on a fifteen-month deployment, that’s an unheard-of amount of action. By the time the U.S. pulled out of the Korengal in April 2010, nearly fifty American soldiers had been K.I.A. there. Seventy percent of ordinance dropped throughout Afghanistan during the course of the war was dropped here. In an interview with CNN, Junger describes the Korengal as “the Afghanistan of Afghanistan, too remote to conquer, too poor to intimidate, too autonomous to buy off.”

Captain Dan Kearney, newly-installed director of the unit in which Junger and Hetherington were embedded, put it more succinctly in describing his reaction to arriving in the valley: “What are we doing?” This is the question every soldier asked every day, sometimes answering it in different ways, sometimes not answering it at all. The reality of not knowing how close the danger will come soon becomes a reality of knowing, uncomplicatedly, that the danger will come. Several brothers from the unit are K.I.A. throughout the tour, including medic Juan “Doc” Restrepo. The unit named the second outpost, a base they established in the heart of enemy territory, after their fallen comrade.

What makes Restrepo so potent in a sea of war documentaries? What sets it apart from Junger’s War or the Vanity Fair series, or even from the strongest fictionalized accounts of modern American warfare like The Hurt Locker or American Sniper? You might think the immediacy of getting to know the soldiers in the Korengal before, during and after battle would provide the brunt of the drama, and that drama certainly is both efficacious and distinctive. Operation Rock Avalanche, the mission that most of the men cited when asked about the low point of the tour, is a harrowing portion of Restrepo that’s difficult to watch. Countless instances throughout the documentary highlight the incredible threat posed to anyone in the valley.

But the action is never the most gripping thing about Restrepo. When I asked Junger on the Boston press junket about the experience of putting the documentary together concurrently with penning War and publishing the Vanity Fair journals, he noted that even the most impressive footage of the most dangerous mission was never as fascinating as the emotion on the human face. The intimate interviews with the soldiers as they stopped in Italy on the way home to the States provide the real clout of the film, especially when paired with the real-time footage of life (if you can call it “living”) in the Korengal; the battle footage is ostensibly more chaotic and dramatic, but the interview footage drives the depth of the entire piece.

Operation Rock Avalanche, for example, is prefaced by recantations of the brutality of that particular mission by several soldiers before we ever get any actual footage of the operation. Earlier we see Misha Pemble-Belkin, a babyfaced and earnest young member of the unit, admitting his concern over the naming of such a desolate-seeming outpost after their good friend Restrepo. When Rock Avalanche goes bad we feel the effect of it, and when OP Restrepo grows into a vital base worthy of the fallen medic’s name we feel the pride of the accomplishment — not because we know the story, but because we know the men who lived the story.

Junger followed Restrepo with Korengal, a sequel crafted from unused footage that he and Hetherington took from that same tour, and also capped off the de facto trilogy with The Last Patrol. Those films are powerful, as is Junger’s tribute to Hetherington following his death while covering the conflict in Syria (titled Which Way Is the front Line from Here?) and all of the fantastic writing Junger produced from his time as a war journalist. Restrepo is unique, though, and remains one of the most important films about the American soldier in our time.