The Mitfords: Letters Between Six Sisters, looks at 80 years worth of letters written by the Mitford sisters, who were born into British aristrocracy.
The sisters' lives were bound up with the many of the great upheaval and leaders of the 20th century. Two of the sisters were close friends of Adolf Hitler, another was an ardent communist and another was a famous novelist.
The book is a collection of letters from sisters Nancy, Pamela, Diana, Unity, Jessica and Deborah Mitford.
Scott Simon talks to the book's editor, Charlotte Mosley, and Deborah, the Duchess of Devonshire, who's the last surviving Mitford sister.