It's all about Valli's voice—a soaring, gravity-defying phenomenon that easily scales three octaves. With his backing group The Four Seasons, Valli built a bridge between doo-wop and pop, combining rousing harmonies, yearning lyrics, big tunes, and lead vocals that never quit. From chirpy, upbeat songs with the group to his intensely romantic ballads as a solo artist, Valli oozes charm and exudes energy, while the bouncy blend of voices and sparkling instrumentation fuels hummable hits that proved to be irresistible and enduring.