I’ve been passionate about the Prisoners Rights Movement for about two years now, and the most recent book I’ve read (and recommend) about it is The New Jim Crow : Mass Incarceration in the Age of Colorblindness by Michelle Alexander. Powerfully written, Alexander gives reasons for the prison explosion of the past thirty years, how it relates to the war on drugs, and how the war on drugs has so effectively been used to lock up (at least) half of a generation of black men, consigning black and brown people (once again) to second-class citizenship. Please consider visiting this link http://www.writeaprisoner.com/ (or just click on the photo) for information on how to become a pen-pal with a prisoner.
Also, this is actually a Canadian poster - as far as I can find, the United States has no day devoted to prisoners rights or the prison movement. Go Canada!