The Repo Man Sings For You
Mickey Hess (editor), Hip Hop in America, A Regional Guide: Volume I East Coast and West Coast (2010)
This book has a fine section on The Coup as an example of funky, political West Coast hip-hop.
John Malkin, Sounds of Freedom: Musicians on spirituality and social change (2005)
Check out an interesting interview with Boots Riley, who doesn't believe in god but does believe in a spiritual role for music.