In technology, synergism is a doctrine that regeneration is effected by a combination of human will and divine grace. In song, synergism couldn’t be better personified than a Jazz Fest concert bill on May 4, featuring Joan Baez, the Indigo Girls and Joan Osborne. The result of such a creative grouping could be something quite special, maybe even synergistic.

1959. Joan Baez, the quintessential teenage beatnik - long straight black hair, turtleneck, sandals, quirky, lite...