"Always And Forever" is not a phrase usually associated with a fickle music business, especially in recent times when one-hit wonders and manufactured artists have been especially prevalent. But for Silk, one of the few vocal groups to breakthrough in the hip-hop era, the phrase applies not only to their own longevity--seventeen years and counting with the current line-up featuring the four original members who have been together throughout--but also to the quality of their music which