Like many gentlemen of his time, Charles Darwin married his first cousin. In fact, marriages between close relatives were commonplace in nineteenth-century England, and Adam Kuper argues that they played a crucial role in the rise of the bourgeoisie.

Incest and Influence shows us just how the political networks of the eighteenth-century aristocracy were succeeded by hundreds of in-married bourgeois clans--in finance and industry, in local and national politics, in the church, and in intellectual life. In a richly detailed narrative, Kuper deploys his expertise as an...