One's appreciation of a beautiful painting is enhanced by knowing about the aesthetic choices the artist made in composition and execution of the painting. It is also enhanced by knowing how the artist's selection and use of materials - and their interplay with light - affects what we see in the painting. This book discusses the physics and materials science that go into making a painting appear the way it does: the physical principles behind the colors one sees in paintings and how they change with illumination; the pigments, binders, varnish, and support materials used in both old and modern paintings; the optics and microscopic structure of paint films; and the various physical and chemical methods used to investigate and authenticate paintings. Chapters on dating, binders, and dendochronology are contributed by experts in the respective fields. Based on courses given at Cornell and Arizona, the treatment requires no prior knowledge of physics or chemistry. The insights gained from this book can help the amateur or connoisseur and also the artist understand the advantages and limitations of materials used in paintings, and it can help the historian and conservator authenticate and preserve works of art.