“Twenty years ago, synesthesia – the automatic conjoining of two or more senses – was regarded by scientists (if at all) as a rare curiosity. We now know that perhaps one person in twenty is synesthetic, and so we must regard it as an essential, and fascinating, part of the human experience. Indeed, it may well be the basis and inspiration for much of human imagination and metaphor. No one has done more than Richard Cytowic and David Eagleman to bring a careful neuroscientific attention to synesthesia, grounded in decades of research and reports from thousands of patients. Their work has changed the way we think of the human brain, and Wednesday Is Indigo Blue is a unique and indispensable guide for anyone interested in how we perceive the world.” – Oliver Sacks, author of The Man who Mistook his Wife for a Hat

“This is a clear, clever book that will appeal to synaesthetes in search of explanations, and to all with a passion for neurology’s wild territory.” – New Scientist

“An invaluable introduction to the phenomenon of synesthesia…. a well-structured exposition of the vast, rich literature on the subject. The text is richly illustrated, adding to the readers’ understanding of the process. This well-written summary of what is known about synesthesia concludes with some helpful suggestions for the direction of future research. Summing Up: Highly recommended.” – Choice Magazine

Wednesday is Indigo Blue adds a new and rich philosophical discussion and a variety of cognitive neuroscience experiments to the topic of synesthesia. Cytowic and Eagleman make a convincing case that research on synesthesia has and will significantly contribute to our understanding of the brain’s neural networks.” – Harry A. Whitaker, Department of Psychology, Northern Michigan University

“A fascinating survey of the enormous variety and creativity of the synesthetic mind.” – Daniel Tammet, synesthete and author of Born on a Blue Day

"David Eagleman may be the best combination of scientist and fiction-writer alive."
- Stewart Brand
"What Eagleman seems to be calling for is a new Enlightenment."
- Sunday Herald
"David Eagleman is the kind of guy who really does make being a neuroscientist look like fun."
- New York Times
"A popularizer of impressive gusto...[Eagleman] aims, grandly, to do for the study of the mind what Copernicus did for the study of the stars."
- New York Observer
"[A] neuroscientist and polymath."
- Wall Street Journal
"Eagleman has a talent for testing the untestable, for taking seemingly sophomoric notions and using them to nail down the slippery stuff of consciousness."
- The New Yorker
"David Eagleman offers startling lessons.... His method in both Sum and his new book, Incognito, is to ask us to cast off our lazy, commonplace assumptions."
- The Guardian