Chance ordained that Denis Diderot (1713-1784) was not only a philosopher, playwright and writer, but also a salonnier. In other words, an art critic. In 1759, his friend Grimm entrusted him with a project that forced him to acquire "thoughtful notions concerning painting and sculpture" and to refine "art terms, so familiar in his words yet so vague in his mind."

Diderot wrote artistic reviews of exhibitions Salons that were organized bi-annually at the Louvre by the Academie Royale de Peinture et de Sculpture. These reviews, published in the Correspondence...