A survey of the various understandings of sensibility that passed back and forth between different professional modes of discourse in 18th-century France. The thrills of the nervous system, the delectations of taste and the pangs of the heart mattered as much in the laboratory as in literature. The author shows that the multiple junctures between the body and the mind promoted a steady commerce between science and the salons. Anne Vila looks into that commerce and its changing purposes in the course of the 18th century. She examines works by influentual authors - Diderot, Rousseau, de Laclos, Sade - to determine the significance of the sentimentality which they both absorbed and helped define. But she also steps beyond belles lettres and investigates the medical, biological, and philosophical literature of the period the reveal deep and continuous interrelations. If moods are as contagious as colds and wickedness is as debilitating as a bad diet, the inquiries of the 18th century still have much to tell.