This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book suggests that art history needs to rediscover its analytic techniques of the visual and fundamental intellectual interests in questions of the visual nature of works of art. Although visuality is the defining characteristic of the arts of painting and architecture, the intense thematization of that concept is a recent development. The earliest Renaissance theorists of painting, Cennino Cennini and Leon Battista Alberti, discussed painting in terms of making present by pictorial means what is absent or invisible. The book attempts to tease out the substantial intellectual issues at stake. It discusses the ways in which this situation has arisen out of the very constitution of art history and the nature of its historiographical development in the nineteenth and twentieth centuries.