Introduction

This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book summarizes results collected over a period of 26 years with John, a patient with a disorder known as integrative visual agnosia. One of the interesting aspects of John's case was that the stroke was both highly selective but also had widespread effects on his vision. There were problems in recognising common objects, faces, seeing colours, reading and finding his way around his environment. For each of the visual problem, John's case provided a unique insight into the nature of the underlying process. The Stroke Association has supported the authors' work for over 30 years and this has been a mainstay of their research group. The book presents many of the articles on John so that readers are able to gain ready access to the different studies.