S ame years ago, I was silling in the noisy back room of a record store on Twelfth Street in Detroit. Twelfth Street had become the main artery of the black sector after the more (amaus Hastings Street had been removed to make room for an expressway. My companion was a blues pianist named Vemon Harrison, although he was known locally only by the nickname Boogie Woogie Red. I asked hirn why he played the blues, and what the blues meant to hirn. He didn't hesitate to reply, but just started to play and talk while I wrestled with my tape recorder. Ta me, Boogie Woogie Red's spontaneous reply was a remarkable definition of the blues: "It's something that you play when you are in a lew mood; it has to carne frorn the heart. But, there's so much good feeling in the blues that comes {rom playing it. "