If you are looking for a general overview of the concept of synesthesia, I would not recommend this book. This book is instead for the serious student or professional who is interested in the field of synesthesia and what research is being done to define and document it. The book primarily consists of highly detailed descriptions the various experiments done on synesthetes (people who experience synesthesia) and the outcomes of those experiments.
Further, the book almost entirely dicsusses grapheme-color synesthesia, or synesthesia experienced by associating numbers and letters with specific colors. Other forms of synesthesia are mentioned, but all of the experiments appear to be related to the above-mentioned version of the experience. Finally, the book is appropriately deadpan, offering only that this and that experiment suggests this and that. There is no emphasis whatsoever on spiritual issues or anything "New Age."
The book is well-organized and articulate, but highly technical while being only mildly conceptual. Most of the experiments mentioned define what synesthesia is *not* rather than what it is. Its most important contribution is the emphasis on describing the machines used to do experiments as well as the non-mechanical experiments (having synesthetes read combinations of numbers on black-and-white or color surfaces, for example) used to define the condition.
The fact that the book does not ultimately define the properties of synesthesia is perfectly understandable considering the limitations of how we can study it at this time. The explanations of how the human brain and mind are defined by scientists are concise and certainly useful for both scientists and philosophers as well as more technically-minded artists. I would recommend this book to anyone interested in the study of human perception.
