In 1969 Gerhard Kubik chanced to encounter a Mozambican labor migrant, a miner in Transvaal, South Africa, tapping a cipendani, a mouth-resonated musical bow. A comparable instrument was seen in the hands of a white Appalachian musician who claimed it as part of his own cultural heritage. Through connections like these Kubik realized that the link between these two far-flung musicians is African-American music, the sound that became the blues...