By any measure of talent and accomplishment, Lisa Fischer is a superstar. Yet, if you do not know her name it is likely because Fischer has spent the last 20 years as a backup singer for the Rolling Stones, Sting, Chris Botti and countless others. It’s easy to see why she works all the time. Her astonishing range, her spot-on intonation and her mastery of the stage keep her on top of the call list. The breakout documentary Twenty Feet From Stardom raised Fischer’s profile so high that she is taking her show on the road and audiences are riveted by her interpretations of classic songs from across the rock and pop universe.