Lovely of face and figure, Valerie Masterson established herself as an important artist early in her career, making special claims on areas of the French repertory, in the works of Gilbert and Sullivan, and as an engaging interpreter of songs from popular musical theater. Her slender, slightly acidulous voice proved well suited to such roles as Manon, Marguérite, and Micaëla. After studies at the Matthay School of Music in Liverpool and at London's Royal College of Music, Masterson traveled to Milan to work with Adelaide Saraceni, a former soprano who was remembered especially...