Jeff Greene grew up listening to music, from the blues in his boyhood Chicago to the eastern modal music he encountered hitchhiking across the Sahara Desert as a teenager. When a project in Nashville led him to rediscover American roots music, he dug a little deeper and traced it back to its Celtic traditions, which in turn led to a whole world of folk music from all over Europe—back through the Balkans and Klezmer music, back to the Ottoman Empire and beyond, to Persia and the Indian subcont...