The author provides another piece of American history which likely was not covered in your schools.
After the Civil War, the 13th, 14th, and 15th Constitutional amendments were passed with the intention of establishing equality under the law for newly freed slaves, or so the story goes. The fact of the matter is that slavery was - and still is - completely legal in the United States, only in a much different form.There is also an excellent PBS 1:24:56m video by the same title based on a book by this title authored by Douglas A. Blackmon who Douglas-Bowers also references.