In this book, an eminent art historian draws on contemporary cognitive science, eighteenth-century theories of visual perception, and art history to discuss shadows and the visual knowledge they can offer. Michael Baxandall begins by describing the physical constitution and different varieties of shadows. He then sketches the eighteenth-century empirical/nativist debate on the role of shadows in the perception of shape. Next he surveys modern research by cognitive scientists and machine vision workers, explaining how research is divided on the issue of how far and by what means shadows help or hinder perception of shape. Baxandall continues his exploration by recounting a neglected episode of shadow theory, the observations of a group of mid-eighteenth-century French scientists and artists on shadows as related to light and space. Finally he sets these various shadow universes into relation with each other, addressing the special problem of painting shadows, and analyses Chardin's painting The Young Draughtsman, in which shadow painting is both medium and theme. The book includes an appendix that situates and summarizes the shadow system of Leonardo da Vinci, which has had a strong though partly underground influence on thinking about shadows for five hundred years.