Even ardent Mitfordians must quake at the sight of yet another biography of the sisterhood. There have been more forests felled in the name of Nancy, Pamela, Diana, Unity, Jessica and Deborah Freeman-Mitford than the Brontë sisters. Jessica alone produced two volumes of memoirs, Hons and Rebels (1960) and A Fine Old Conflict (1977); her collected letters (Decca, 2006) came in at a thumping 700 pages and in 2010, Irrepressible, Leslie Brody’s biography of Jessica’s years in the United States, appeared.