The hideous chapter in American history had passed, and the slaves were freed – or so everyone thinks.

PBS’ gripping documentary “Slavery by Another Name,” airing tonight, chronicles how slavery continued in the South well into the 20th century while the rest of the country ignored it. Laurence Fishburne narrates.

“What I really want people to take away is you can’t partition parts of our history,” says Dr. Sharon Malone, who is featured in the film. “There is not Southern history; it is American history.”

Malone, an obstetrician, is a sixth-generation Alabaman married to U.S. Attorney General Eric Holder. Her older sister, Vivian Malone, helped integrate the University of Alabama in 1963, protected by the Justice Department, which Sharon’s husband now runs. Malone’s uncle, Henry Malone, was arrested and served a year and a day in Alabama’s Monroe County under the peonage system. Precisely what, if anything, he had done is not known.

The peonage system was how slavery continued.

Douglas A. Blackmon’s Pulitzer Prize-winning book, “Slavery by Another Name,” upon which the 90-minute film is based, details the peonage system. Though most people believe the Emancipation Proclamation ended slavery, blacks were re-enslaved to work, without pay, in coal mines, cotton fields and brickyards. They were shackled, beaten, bought and sold.

They were slaves.

And this was all done under the thinnest veil of legality. Though the 13th Amendment abolished slavery, there was a loophole: except in the case of punishment for a crime.

And crimes for blacks included talking loudly in the presence of a white woman, leaving one job for another, selling cotton after dark and walking along railroad tracks.