In the second edition of his book Synesthesia: A Union of the Senses, Dr. Cytowic draws on his intimate knowledge of the development and workings of the human brain, as well as his ample experience with synesthetic patients of various ages and backgrounds, to define the basic characteristics of the phenomenon, search for a probable location for the physiological integration of synesthetic percepts, and relate synesthesia to common neurological processes that allow each one of us to interpret our surroundings. Along the way, Cytowic provides a current model of the architecture and connectivity of the brain and neural tissues, as well as some interesting examples of how synesthesia can inspire the creation of art and music.