The quintessential Chicago soul group, the Impressions' place in R&B history would be secure if they'd done nothing but launch the careers of soul legends Jerry Butler and Curtis Mayfield. But far more than that, the Impressions recorded some of the most distinctive vocal-group R&B of the '60s under Mayfield's guidance. Their style was marked by airy, feather-light harmonies and Mayfield's influentially sparse guitar work, plus, at times, understated Latin rhythms. If their sound was sweet and lilting, it remained richly soulful thanks to the group's firm grounding in gospel t...