William Cavendish, the father of the first Earl, dissolved monasteries for Henry VIII. Bess, his second wife, was gaoler-companion to Mary Queen of Scots during her long imprisonment in England. Arbella Stuart, their granddaughter, was a heartbeat away from the throne of England and their grandson, the Lord General of the North, fought to save the crown for Charles I.

With the help of previously unpublished material from the Chatsworth archives, The Devonshires reveals how the dynasty made and lost fortunes, fought and fornicated, built great houses, patronised the arts and pioneered the railways, made great scientific discoveries, and, in the end, came to terms with changing times.