Recent theoretical developments and research findings from three different approaches to visual perception are brought together in this book. The first approach is physiological; the evolution of different types of eye and the physiology of mammalian visual pathways are described. The second is the traditional psychological approach; perceptual organization, the perception of depth and motion, and pattern recogniton are discussed in terms of the processing of information contained in retinal images. Emphasis is placed on recent computational work on these processes, and particularly on algorithms for the detection of edges and motion, the computation of stereo disparity, and object recognition. Connectionist approaches to these problems are discussed and contrasted with those of theorists such as Marr. The third perspective considered is ecological; the work of Gibson and his followers is described and applied to problems of animal and human locomotion, even perception and perception of the social world, including the human face. The book stands out from other texts on visual perception in treating both the computational and ecological approaches in detail, and in seeking to clarify the points of contact and controversy between them. It is also distinctive in placing emphasis on animal vision as well as that of humans. Aimed at advanced undergraduate psychology and zoology students, this book will also prove of value to postgraduate students and research workers. The book has been updated and substantially enlarged in its second edition, in particular to include new material on connectionism, the computation of motion and the primal sketch.