Black History Month has become a marketing ploy, a way for entertainment publicists to plug African American clients, a quick and easy way to segregate the telling of what is American history into 28 days, the time of year that one bard quipped is "the only month where a black poet can get work."

Part of this is the notion that history is a dead thing, and that African American history is something that happened to other people. But with HBO's new documentary, "Unchained Memories: Readings From the Slave Narratives," what many view as ancient history breathes with life: life that is at times bitter, angry, despairing, defiant and, for those who survived it, transcendent. (The documentary airs tonight at 8 and will air again throughout the month.)

"If I had my life to live over," says Don Cheadle, reading from the narrative of real-life slave Robert Falls, "I would rather die fighting than be a slave again."

In the 1930s, Falls was one of 100,000 former slaves who were still alive. It was the time of the Great Depression, and hundreds of writers were out of work. The Works Progress Administration's Federal Writers' Project put many of those scribes to work, traveling the country, interviewing the last generation of African Americans born into bondage.

The last generation who could describe firsthand what it was like to live, as one bill of sale read, as a "slave for life." From 1936 to 1938, more than 2,000 interviews were conducted. They now are on file in the Library of Congress, which is a partner with HBO in the production.

With "Unchained Memories," narrated by Whoopi Goldberg, those interviews are given vibrancy with an interesting device: the staged readings by the likes of Angela Bassett, Michael Boatman, Ossie Davis, Ruby Dee, Robert Guillaume, CCH Pounder, Roger Guenveur Smith, Vanessa Williams, Oprah Winfrey and Alfre Woodard.

The readings are done on simple sets, with the camera homing in on the actors' faces. We see their reaction to the subject matter and its legacy: Samuel L. Jackson recalling his own grandparents' stories of Jim Crow Georgia, the tears in Roscoe Lee Browne's eyes.

The 74-minute documentary's power lies in its understatement, in the lack of theatrics to depict a shameful, centuries-long episode in American history. The narratives are written in the vernacular of the freed slaves -- or, rather, the often-white interviewers' attempts at the dialect. The N-word is used liberally, matter-of-factly, without irony. That's what they were called by their masters, and that's what they called themselves.

"Lord, lord, honey," one remembers. "Them was some awful days." And indeed, they were.

Slave life is chronicled from birth to childhood to adulthood, from marriage to death, from beatings to escape, from spirituality to sly revenge.

The world they describe is a complex one, where, on the one hand, Cato Carter can boast about how well he was treated in the Big House because he had "the same blood" as his white slave-owning relatives, and then, describe how he ran away from his beloved plantation because one of his masters ordered him to kill another slave. He told the slave that they both had to run. And so they did.

"I hated to go," Carter says, "but today I is an old man and my hands ain't with no blood."

They tell of children huddling together on the floor, sleeping close to each other lest they should freeze to death, of them eating together out of a trough, humans treated like livestock. There are tales of rape, of a woman being tied up and being raped for an entire day by her mistress's three sons.

A former slave, whose words are read by Jasmine Guy, describes the incident dispassionately. And then comes the jarring denouement: "And that's how I came to be."

That's a critical part of how this country came to be, and it's a shame to see it tossed in the dustbins of history. Then, too, shame is a part of why it is all too often relegated to a footnote: shame on the part of those who descended from slave owners, and those who descended from slaves. (And quite often, as "Unchained Memories" illustrates, African Americans descended from both.) It's a shame, too, that documentaries tend to have such limited audiences, that they often don't have a lot of power to influence the national dialogue. "Unchained Memories" honors the more than 4 million who survived slavery, those like Katie Rowe, whose words marked the day of her freedom in 1865 as the day "I begins to live, begins to live, begins to live."

Roger Guenveur Smith and Jasmine Guy are readers in "Unchained Memories: Readings From the Slave Narratives," premiering tonight on HBO.

In the documentary "Unchained Memories," airing tonight on HBO, Samuel L. Jackson and Oprah Winrey read narratives from the days of slavery and Jim Crow with efficacious dispassion.