When people describe Southside and Westside Chicago as a "war zone," they're not being histrionic. In 2008, according to the Chicago Tribune, there were many more Americans murdered in Chicago (508) than were killed in Iraq (319).

So what are people doing about it? Police show up after the shootings, though it doesn't seem to deter the violence—cops will routinely get called away from one fresh murder scene to chase down another (then another, then another, then another) within a few blocks' radius. News cameras show up when there are marches or angry community meetings, but they evaporate just as quickly. In one scene of The Interrupters, an exquisitely harrowing documentary by Steve James (Hoop Dreams), a Chicago resident shouts angrily during one street-corner press conference, "Who's gonna be out here before things happen?"

Enter the Interrupters—a cadre of ex–gang leaders hired by an organization called CeaseFire—who go into the streets, break up fights, and try to negotiate peace settlements between individuals, cliques, high schools, and families at war. They never take sides and they don't try to dismantle the gangs. (Each of them is intimately familiar with a gang's appeal.) The Interrupters simply, in the words of Tio Hardiman, CeaseFire's director of field operations, "try to save a life."

Hardiman says he got pushback when he first started hiring ex-cons, murderers, former gang enforcers, and gang leaders (including a guy who earned his nickname, "The Gladiator," because every member of his gang had to fight him before moving up the ranks). But these people are, Hardiman argues, the only ones with the street cred to wade into charged situations that are bristling with guns and tell everybody to stand the fuck down. One example: Ameena Matthews, daughter of Chicago gang legend Jeff Fort, who was a drug-gang enforcer herself. The film catches her doing street-corner preaching to young gangbangers, getting right up in their faces, making them flinch—but also documents her quietly cooing and mothering when she needs to, comforting the comfortless. Her confidence and emotional bandwidth are almost superhuman.

While The Interrupters presents its characters in deeply poetic ways, its picture of life on the Chicago streets is anthropological, almost scientific—it doesn't judge anyone, cops or gangbangers or politicians. The filmmakers may have derived this attitude from Gary Slutkin, MD, an epidemiologist who founded CeaseFire and sees violence in terms of disease. People with smallpox and the plague used to be seen as "bad," he argues, and violence is the same way. What perpetuates violence now can be as invisible to us as the microbes that caused disease were to people then. The Interrupters, he says, are like tuberculosis physicians—their job is to prevent the transmission.

Hardiman echoes this sentiment later in the film. "It's a myth that most of the violence is gang-related," he says. Though many of the people involved in the violence have gang affiliations, it's more about simple "interpersonal conflict" and the code of death before dishonor.

Simply put (and at the risk of sounding corny), The Interrupters is a profound portrait of human beings at extremes: of fear, of anger, of courage, of love. It is also one of the best documentaries I have ever seen. Go.