Sight Unseen: An Exploration of Conscious and Unconscious Vision, MelvinGoodale and DavidMilner. Oxford University Press, Oxford, UK, 2004, 49. 50

Melvin Goodale and David Milner. Oxford University Press, Oxford, UK, 2004, 49. 50 Melvin Goodale and David Milner are prominent visual neuroscientists who have provided some of the most convincing evidence for the presence of two visual streams: a dorsal stream concerned with action and a ventral stream responsible for conscious perception. This book describes 15 years of research that they, as well as others, have spent exploring these pathways. The authors begin by using the case study of a patient, Dee, who suffered damage to her ventral pathway as a result of carbon monoxide poisoning, as a means to illustrate the existence of these two pathways. The rest of the book describes a wide variety of research in the context of explaining how Dee's injury has affected her vision. Early chapters describe the behavioral and neural evidence for the two pathways. The next few chapters describe these pathways in more depth and argue that they differ not only in their functional roles but also in the way that information is represented. The authors argue that the dorsal “action” pathway is viewpoint dependent and uses world metrics, whereas the ventral “perception” pathway is object based and uses metrics based on relative size. The authors then describe how these two types of processing interact and argue that “consciousness” is solely associated with the ventral stream. Finally, the authors return to Dee and describe her visual function 15 years after her accident. In terms of material and organization, this book closely resembles The Visual Brain in Action, a book for specialists published by the same authors. Possibly as a result, this book is probably a little less approachable to a general reader than the authors intended. I know of almost no literature explaining visual processing and the effects of cortical damage that is written at a level suitable for patients with cortical blindness (or their families). For the more sophisticated, this book should be invaluable, but I think the majority of patients will find it a little too academic. However, because the book reviews 15 years of research on an important and fascinating topic in neuroscience, it provides an excellent perspective on how science progresses through the gradual accumulation of evidence. The book also touches on a wide array of important questions in vision while remaining unashamedly speculative. As such, it would make superb course material that should provoke discussion in either a high-level undergraduate or early graduate course. Clinicians looking for a theoretical overview of visual function with an emphasis on the effects of visuocortical damage would also find this book interesting. I would have like to have been provided with more of an insight into Dee's perspective. The authors note that it is difficult for Dee to describe her visual experience: “we are asking Dee to talk about what she doesn't see—we are asking her to describe what is not there in her conscious experience. ” But still, presumably Dee remembers what it was like to live life with normal vision? She should be able to describe which activities she now finds particularly difficult. In a fascinating postscript describing Dee's visual performance 15 years after the accident, the authors describe Dee's ability to perform a variety of visual skills. They describe various examples of her sophisticated compensatory strategies; but again, it would have been interesting to know whether Dee has any insight into how she has gradually learned to compensate for her visual deficits. As may be expected from Oxford University Press, the general esthetic is appealing. A minor criticism is that the neuroanatomic data are represented in a wide variety of formats and orientations. This makes it difficult (and probably impossible for a general reader) to compare patterns of neural activity across the different plates. Ione Fine Department of Ophthalmology Zilkha Neurogenetic Institute Keck School of Medicine University of Southern California Los Angeles, California