The New Jim Crow Mass Incarceration in the Age of Colorblindness by Michelle Alexander. Cornel West also wrote a "New Forward" to the edition I foiund in paperback at the library.
There is a link to a pdf of perhaps a precursor to the book at:
Check out the google books preview at:
googlebooks brief review:
"Argues that the War on Drugs and policies that deny convicted felons equal access to employment, housing, education, and public benefits create a permanent under caste based largely on race."