On any Sunday afternoon a traveler through the Deep South might chance upon the rich, full sound of Sacred Harp singing. Aided with nothing but their own voices and the traditional shape-note songbook, Sacred Harp singers produce a sound that is unmistakable--clear and full-voiced. Passed down from early settlers in the backwoods of the Southern Uplands, this religious folk tradition hearkens back to a simpler age when Sundays were a time for the...