When we began the task of preparing a second edition of this book, we were unsure how much of the original structure and content should be retained. After all, there have been far-reaching developments in visual science during the last decade. Also, we now have experience of students' responses to the book, and the benefit of views from many colleagues. As a result there have been considerable changes, and many sections have been rewritten. However, the essential structure of the book is unchanged. It is still based on a functional approach to vision as a basis for action, and the core chapters are those concerned with perceiving the location, motion, and identity of objects in the environment. The introductory chapter has been rewritten and expanded, as has the following chapter on the historical roots of modern concepts about how we see. The chapters on location and motion retain the same emphasis on defining the frames of reference within which object characteristics are represented, but we have sought to make the development of the ideas clearer and more accessible to students. The conceptual model that informed our analysis of space and motion has itself evolved in the last decade, and shadows of these developments are cast in the core of the book and in the Summary and Conclusions. The chapter on recognition (Chapter 6) has been radically revised, and we have included sections on the major theoretical approaches to this topic. Nevertheless, we have retained the original basis for this account, which is the definition of the representations on which object recognition can be based and how this can be derived from visual and other sensory stimulation. A new chapter on the perception of visual representations such as pictures has been added (Chapter 7). This includes a section concerned with the perception of computer-generated images, which is an increasingly pervasive aspect of visual experience.
Much of what was said in the Preface to the first edition is still entirely relevant to the second edition. However, we have decided to introduce a limited number of references in the body of the text, and we hope that this will help students with the critical transition to learning from a wider range of sources. We hope that the book will normally be read as a whole, but it is also possible to use various chapters independently or in groups. Chapter 2, “The Heritage”, can be read on its own, or omitted if historical issues are not