It would be difficult to find, in European civilization in the last two centuries, two sisters who achieved more success across the arts and professions than Fanny and Adelaide Kemble, the subjects of Ann Blainey’s engrossing twin biography. Born in 1809 to a celebrated theatrical family, Fanny was the most famous English-speaking actress of her day before she left the stage to marry the Philadelphia slave-owner Pierce Butler. For more than sixty years she was seldom out of the public eye, acting in plays, writing books (her classic account of slavery during a stay on a Georgia plantation is still in print), reading Shakespeare in front of large audiences, and fighting for the abolition of the slave system. Her searing intellect and indomitable personality made people love her or hate her; no one could ignore her. Her sister Adelaide, five years her junior, ranks among the finest of English-born opera singers. Making her debut in Venice in the exacting role of Norma—and singing nothing but a leading role thereafter—she won acclaim across Italy and at two brilliant seasons at London’s Covent Garden before marrying the rich Edward Sartoris. The real love of her life, however, was Count Francis Thun, son of one of the great families of the Austrian Empire; her love for Francis hovered over her marriage like a cloud. Fanny never quite forgave Adelaide her success. As Fanny’s own marriage disintegrated, her jealousy surged, and her biased appraisals of her sister’s singing have unfairly tarnished Adelaide’s opera reputation. In many ways, however, as Ms. Blainey shows, the sisters loved each other fiercely. Their complex and fascinating relationship is one of the major themes of this grand biography, based in part on hundreds of family letters to which the author had exclusive access. With 8 pages of black-and-white illustrations.