In 1980, Richard Cytowic was having dinner at a friend's house, when his host exclaimed, "Oh, dear, there aren't enough points on the chicken." With that casual comment began Cytowic's journey into the condition known as synesthesia.The ten people in one million who are synesthetes are born into a world where one sensation (such as sound) conjures up one or more others (such as taste or color). Although scientists have known about synesthesia for two hundred years, until now the condition has remained a mystery. Extensive experiments with more than forty synesthetes led Richard Cytowic to...