In his last work, Colas Duflo explores the corpus of libertine novels with a philosophical bent, showing their impact on the European culture in the 18th century. These clandestine and pornographic works were more popular than philosophical treatises and played a crucial role in spreading some unconventional ideas of the Enlightenment. Duflo discusses the moral and metaphysical ideas that underlie the most relevant among these works, such as Dom Bougre, Thérèse philosophe, Les Bijoux indiscrets, Juliette and Le Rideau levé. The author focuses on the peculiar combination of pornographic fiction and philosophical dissertation, on the diffusion of materialistic thesis and on the distortion of the legacy of the Enlightenment by Sade.