Hamza El Din's "Escalay - The Water Wheel" became a college favorite when it was released in 1971 - one of the first releases on the then-new Nonsuch Explorer label. Joan Baez was one of the Nubianmusician's early supporters - she got him his first recording contract. Back then - before "world music" was a buzz phrase - Hamza El Din was exotic for Americans. But he's always considered himself a serious composer, creating new music for ancient instruments. Karen Michel has a profile.