In John Huston’s classic 1943 documentary, The Battle of San Pietro, American soldiers run into battle, gunfire all around. They fall backwards into trenches, the camera jolting with the concussive force of the explosions. Eventually we see corpses placed into body bags. That harrowing immediacy is one reason James Agee called it “as good a war film as any that has been made,”—but it was entirely fake, staged with the help of the U.S. military to create better propaganda. Along with other staged documentaries, it was presented to the public and swallowed as an authentic work of non-fiction.

This deception, along with stories of other staged World War II docs, is vividly detailed in Mark Harris’ Five Came Back, the history of some of Hollywood’s already-famous directors—Huston, Frank Capra, John Ford, William Wyler, and George Stevens—who volunteered for service and chronicled the war for the U.S. military. The book expansively covers the directors’ entire war experience (Wyler lost the hearing in one ear, Huston suffered PTSD) yet the sections about the fraudulent movies leap out, presenting a healthy challenge to the hagiographic Greatest Generation narrative that has shaped our sense of the war. And the truth resonates strongly with our own era, full of suspicions about government honesty—from the bogus reasons for invading Iraq to NSA surveillance—and our open-eyed acceptance of how fact and fiction merge even in so-called documentaries.

Harris is not the first to unearth this history, although no one else has done it so thoroughly. But most earlier accounts fall in line with the Greatest Generation ideal, making excuses for the deception. Richard Schickel’s 2000 television documentary about World War II photo-journalists, Shooting War, is straightforward about the restagings, but as forgiving as you’d expect from a film with the Saving Private Ryan team behind it: Steven Spielberg as executive producer and Tom Hanks as narrator. Citing Ford’s restaging of the attack on Pearl Harbor, for which there was very little actual film, Hanks notes that Ford shot on a Hollywood lot and even chose to use some reenactments over authentic footage because the scenes matched better. “His goal was not strict authenticity,” Hanks says. “He was out to stir the nation.” Of course, no one bothered to tell the public that when the film was released.

Some of Ford’s fictional touches didn’t have to be labeled for anyone who gave them half a thought: why would cameras have been in sailors’ bunks before the surprise attack? But the story behind San Pietro is more important because the film is so superior. Huston would come to tower over all these directors artistically (only Ford comes close), and his deceptions were far more convincing and sophisticated.

He learned a lot from his experience on an earlier propaganda film, Tunisian Victory, about the Allied campaign in North Africa, a largely restaged work that the U.S. military jointly released with the British. Capra, who ran the Army’s film unit, asked Stevens to shoot reenactments in Algeria. Huston finished the job back home. In California, he recreated ground battles in the Mojave Desert, using fake tanks (metal frames covered in canvas). In Orlando, Florida, he staged air battles. Harris, who maintains a detached historian’s voice for most of the book, calls Tunisian Victory “the sorriest and most shameful episode in the history of army propaganda efforts during World War II.” Huston’s own highly-dramatized autobiography, An Open Book, calls the scenes “trash” and says, “The material was so transparently false that I hated to have anything to do with it.”

But there was nothing transparent about The Battle of San Pietro. Capra’s initial assignment was for Huston to arrive after the Allies had taken the Italian village from the Germans, and film the grateful welcome for the American soldiers. (The idea was a lot more credible back then than it would be 61-years later when Dick Cheney made his famously delusional remark that Iraqis would welcome Americans as liberators.) But the Allied victory was so heavy with casualties that the idea morphed into something tougher.

Huston arrived with a small crew—including Jules Buck, later a successful movie producer, and Eric Ambler, now better known for his spy novels—soon after the battle, in Dec. 1942. They were nearly hit by mortar fire in the still-mined area and quickly fled. Huston and Buck returned in January, and spent six weeks recreating the battle. The U.S. Army gave them soldiers, who sometimes posed as dead Germans. Huston was given guns and, as Harris writes, “access to an extensive and confidential written account of the battle” compiled by the Army, so his restaging would be true-to-life. There was nothing comparable to the Zero Dark Thirty flap about whether the CIA had inappropriately given the filmmakers information. Americans’ attitude toward the government was less questioning then, reporters were more willing to fall in line with the military’s information, and a country at war had other things on its mind.

Huston’s results were magnificent. He slowed down the action at times for effect; he jolted the camera to mimic the jittery imperfection of a documentary. He created an enduring template, as Harris puts it, for “what ‘real’ war film is supposed to look like.” Moving beyond propaganda into art, he created a distinctively John Huston film, writing and narrating a script that was lyrical and at times mordant; over the image of a bombed-out church, his unmistakable deep voice drawls, “Note interesting treatment of chancel.” Yet the film was so straightforward about the harsh reality that some horrified members of the War Department called it “anti-war.”

Even now, The Battle of San Pietro is affecting, with its visceral sense of death, its poetic view of the shattered, rocky village, where a peasant woman walks across rubble carrying an empty coffin. No one wants such an eloquent film to be a fraud. A 2013 military history by Tim Brady, A Death in San Pietro: The Untold Story of Ernie Pyle, John Huston, and the Fight for Purple Heart Valley, is absolutely clear about the Huston reenactments, yet concludes that the film was “a vivid and truthful description of the cost of battle.”

There was no such fudging when the War Department finally released the film, in 1945. One press release stated that “Huston’s first task was so decide how to make his rather small unit spread out during the battle.” The film ends with a title card stating that all scenes “were photographed within range of enemy small arms or artillery fire,” followed by a slippery disclaimer that “for purposes of continuity a few of these scenes were shot before and after the actual battle,” although “a few” here means “nearly all.” It’s hard to imagine such fraudulent lines escaping scrutiny for long today.

Huston never publicly acknowledged that any of San Pietro was fake, not in his autobiography, not in any interview. Why would he undermine a film received as a ready-made classic?

Today, of course, anyone with a phone can shoot war and violence, authentically capturing the jolts that Huston slammed his camera around to fake. Two of last year’s strongest documentaries reveal how far we’ve come from old-style, government-produced propaganda. Jehan Noujaim’s The Square captures scenes from the center of Tahrir Square during and after the protests and government upheavals in Egypt in the past three years. And Joshua Oppenheimer’s The Act of Killing creates a chilling blend of fact and fiction, as members of an Indonesian death squad act out their murders from the 1960’s, reconceived as Hollywood movies. One huge difference, of course, is that Oppenheimer’s dramatizations are clearly fiction based on fact.

Shining a light on the duplicity of the World War II movies adds a layer of ambiguity to the last morally unambiguous war, but the revelations suit today’s culture of information and hoped-for transparency. It takes nothing away from the directors’ genuine bravery to say that their World War II documentaries might be labeled Lies the Greatest Generation Told Us.