Al Kooper's tell-all biography Backstage Passes and Backstabbing Bastards
tells what it's like to work with Chuck Berry: "Early in our careers, we backed up Chuck Berry at his first New York solo concert. He was a scary guy and a tough leader, and never
did he encourage any friendship. He was strictly professional. 'All you do is watch my foot. When it go up in the air, get ready. When it hit the ground, if you playin', stop. If you ain't, start.' That was his mantra."