introduction by Stephen Palmer Irvin Rock was a global perceptual theorist in the grand tradition of von Helmoltz, Wertheimer, and Gibson. This posthumous volume, the culmination of a long and distinguished career, brings together an original essay by the author together with a careful selection of previously published articles (most by Rock) on the theory that perception is an indirect process in which visual experience is derived by inference, rather than being directly and independently determined by retinal stimulation.Rock's reasons for holding that perception is indirect were mainly empirical. Unlike many theorists, he paid close attention to a broad range of experimental evidence in evaluating theoretical claims. His approach, in which theory and experiment go hand in hand, is well represented in this book.In the first chapter, which is new, Rock lays out the theoretical issues underlying indirect perception. The remaining twenty-two chapters present detailed evidence in support of the indirect view. They are divided into sections covering indirect perception, organization, shape, motion, illusions, lightness, and final considerations. Each section is introduced by the author. Stephen Palmer's introduction to the book places Rock's work within the context of the history of perceptual theory -- approaches formulated by Helmholtz (inferential), by the Gestaltist psychologists (organizational), and by Gibson (ecological).Cognitive Psychology series