Brightly hued, highly finished, and relatively large in scale, pastels in the 18th century were regarded as a type of painting and displayed like oils. The powdery, vibrant crayons are particularly suited to capturing the skin tones and evanescent expressions that characterize the most lifelike portraits. Pastels cannot be permanently displayed because they are susceptible to fading, and they rarely travel. Until now, there has never been an exhibition in the U.S. devoted to these intriguing and important works. "Pastel Portraits", the companion book to an exhibition at the Metropolitan Museum, presents over 40 exquisite works by French, Italian, English, Swiss, and American artists. It offers a technical discussion of the materials and explains why pastels achieved widespread popularity in the 1700s and how the fabrication of this medium intersected with Enlightenment thinking.