The Whigs were one of the two great English political parties in the 150 years after 1700, vastly influential whether in office or in opposition. Yet the Whigs were much more than simply a group of politicians. An exclusive set, composed of the greatest and wealthiest families, the Whig world was a self-contained and small one, impervious to outside criticism. With members such as Charles James Fox, Georgiana, Duchess of Devonshire and Lord Byron,...