What is the theme in The Bedroom Philosophers by Marquis de Sade?

Sexual pleasure is a major theme. Eugenie comes to Madame de Saint-Ange's boudoir to be educated in the ways of the flesh, but she receives a more philosophical primer from Dolmance than she could have expected. The renowned rake advises her not only on the mechanics of sex and sado-masochism, but also on the tenets that guide the libertine aesthetic.