The Man Who Tasted Shapes is an extraordinary work of research into the human mind that was, to me, only superficially about synesthesia. The information and perspective shared are much bigger than the title would imply. I believe that you'll find it to be fabulously interesting, even if you have zero interest in synesthesia.
Most doctors are afraid to write what they truly believe in their hearts lest it be challenged and scorned by their peers. Rarely do scientists allow you to "see the man behind the curtain," preferring to hide instead behind that mysterious veil we called "objective data." In this, Dr. Cytowic is far braver than most, and certainly more honest.
Here is just such an example from the book: "My innate analytic personality had been reinforced by twenty years of training in science and medicine. I reflexively analyzed whatever passed my way and firmly believed that the intellect could conquer everything through reason. 'You need an antidote to your incessant intellectualizing,' Clark suggested, 'something to put you in touch with the irrational side of your mind.'... I had never considered that there might be more to the human mind than the rational part that I was familiar with. It had never once occurred to me that a force to balance rationality existed, let alone that it might be a normal part of the human psyche."
In another chapter, Cytowic asserts, "Not everything we are capable of knowing and doing is accessible to or expressible in language. This means that some of our personal knowledge is off limits even to our own inner thoughts. Perhaps this is why humans are so often at odds with themselves, because there is more going on in our minds than we can ever consciously know."
If you read a lot of medical texts, as I do, you will find Dr. Cytowic to be far more broadminded and much less linear in his thinking than his peers. This makes Cytowic interesting, instead of boring like the others.
One final quote: "Neuroscientists have just lately come to realize how important emotion is. Placing reason and the (intellectual) cortex first and foremost is like the Wizard of Oz shouting, "Pay no attention to the man behind the curtain." Reason, and an accomplice called self-awareness have deluded us into believing that they have been pulling the strings, but emotion and mentation not normally accessible to self-awareness have been in charge all along."
The Man Who Tasted Shapes is a delightful bridge between the hard science of neurology and the mystery that is man.
Buy the book. You won't regret it.