When Cherilyn Sarkasian reinvented herself as the more photogenic half of '60s pop duo Sonny & Cher, no one could guess it was merely the first step in an ongoing artistic redefinition that would continue for decades. After the smash success of Sonny & Cher's recordings and TV show, Cher scored pop hits on her own, such as "Half Breed" and "Gypsy...