Dann, Kevin T. Bright Colors Falsely Seen: Synaesthesia and the Search for Transcendental Knowledge. 1998

A history of synaesthesia. From the publisher's blurb: "The author debunks Romanitc notions of the transcendental nature of synaesthesia and shows that although novelist Vladimir Nabokov was a true synaesthete and eidetic, other individuals the Romantics considered synaesthetes were not."