We are reading Toni Morrison's Beloved this week, and the section on Paul D's experience on a chain gang reminded me of a book (and documentary), titled Slavery by Another Name: The Re-Enslavement of Black Americans from the Civil War to World War II, that reports on the systematic use of imprisonment and chain gangs to suppress blacks after Emancipation and to coerce unpaid labor. This work is also relevant to Ellison's Invisible Man, specifically, the character Brother Tarp, who served on a chain gang for many years. His "souvenir" leg chain connects his experience to the experience of slavery, which is also symbolized by a leg chain on display at the narrator's school (modeled on Tuskegee) that comes earlier in the novel.
The book, Slavery By Another Name, by Douglas Blackmon, won a Pulitzer in 2009 (see blurb below). PBS aired the documentary in January 2013. For more on the book and to view the documentary, go to http://www.slaverybyanothername.com/