The Duchess, by Amanda Foreman
I picked this up a year or so ago after seeing the movie that was based on it, the subject matter perked up enormously by the use of Keira Knightley and Ralph Fiennes as the Duchess and Duke. For anyone interested in lush, historical dramas I can recommend it. For anyone interested in a glimpse of Fiennes mostly naked, I can recommend it. As for the book, I've made it to chapter two and am finding it odd going. It mixes the dryness of a textbook with modern psychoanalysis of 18th century minds. Which, for all I know, may be valid but it seems odd to me.
Briefly, it's an account of the life of Georgiana Spencer (ancestor of Princess Di), who went from life as an aristocrat to life as a royal when she married William Cavendish, the fifth Duke of Devonshire and one of the wealthiest men in England. Her life thereafter became one of glamour, duty and excess. Lots and lots of excess, at least according to the movie. Drinking, drug use, gambling and lovers of both sexes. And children, I lost count in the movie but at one point she and a lover she shared with her husband both had a child by him within weeks of each other. I hope the book eventually gets this juicy.