Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia

by Richard E. Cytowic, David Eagleman

A person with synesthesia might feel the flavor of food on her fingertips, sense the letter J as shimmering magenta or the number 5 as emerald green, hear and taste her husband's voice as buttery golden brown. Synesthetes rarely talk about their peculiar sensory gift—believing either that everyone else senses the world exactly as they do, or that no one else does. Yet synesthesia occurs in one in twenty people, and is even more common among artists. One famous synesthete was novelist Vladimir Nabokov, who insisted as a toddler that the colors on his wooden alphabet blocks were "all wrong." His mother understood exactly what he meant because she, too, had synesthesia. Nabokov's son Dmitri, who recounts this tale in the afterword to this book, is also a synesthete—further illustrating how synesthesia runs in families.

In Wednesday Is Indigo Blue, pioneering researcher Richard Cytowic and distinguished neuroscientist David Eagleman explain the neuroscience and genetics behind synesthesia’s multisensory experiences. Because synesthesia contradicted existing theory, Cytowic spent twenty years persuading colleagues that it was a real—and important—brain phenomenon rather than a mere curiosity. Today scientists in fifteen countries are exploring synesthesia and how it is changing the traditional view of how the brain works.

Cytowic and Eagleman argue that perception is already multisensory, though for most of us its multiple dimensions exist beyond the reach of consciousness. Reality, they point out, is more subjective than most people realize. No mere curiosity, synesthesia is a window on the mind and brain, highlighting the amazing differences in the way people see the world.

Genres: Nonfiction, Science, Psychology, Neuroscience, Brain, Philosophy, Biology

309 pages, Hardcover

First published January 1, 2009

About the author

Richard E. Cytowic, MD, MFA is a neurologist best know for bringing synesthesia back into the scientific mainstream in 1980. The trait of crossed senses is now seen as important to understanding how brains perceive.

Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia (with David Eagleman) won the 2011 Montaigne Medal.

Cytowic also writes non-fiction and fiction, and received his MFA in creative writing from American University. The Pulitzer nominee's work has appeared in The Washingtonian, New Scientist, and the New York Times Magazine.

His Blog at Psychology Today is The Fallible Mind: Emotion, perception, and other tricks of the brain

Reviews

[Cheryl · Rating 4 out of 5]

Excited to read more Cytowic books. Perhaps like many syns, as a child and teen, I had always assumed that everyone could taste shapes, personify numbers and associate their alpha and numeric system with color and personality.
It is funny that the title of Cytowic's book contains "Wednesday" because it was the word Wednesday with which I made the revelation that what I experienced was not the norm. My first memory of synesthesia was when I was four years of age (BTW-4,is a medium matte brown), I was in the garage, helping my mother with the laundry, when I noticed the box of detergent she was measuring into the washing machine, which was Tide laundry detergent. I was learning my days of the week and had been reading since I was three. When I saw the box of Tide, with it's neon yellow-into orange explosive colors I noticed how much the colors were like the "color of Wednesday." I excitedly related this to my mom, thinking she'd agree and how clever I was to make this connection, when I noticed she looked puzzled and didn't say much. I remember I felt a little ashamed and realized we were not speaking the same language. I never again brought my colored words, numbers or alphabet up to anyone again.

Fast forward 26 years later. My colored senses are still very much intact, I no longer feel quite so ashamed, but I don't talk about it either - or share my experiences. If anything I subconsciously know that in a weird way whatever this thing I have is, I'm lucky. Unlike a few rare syns, this condition has been more helpful then not. More joyful then not. It has made my life richer. I dont try to get answers about it - I'm okay with the mystery of it and besides my earliest experience told me that talking about it was not a good idea. So, whatever IT is, it doesn't really exist.
I have a memory that is to be reckoned with. Always have. That can mostly be a good thing -quite handy. Sometimes, I wish my memory was like swiss cheese. I don't even realize at this point that synesthesia has a name or is a real "condition" or that it is the subject of much discussion, debate, and scientific study.
So, 26 years later(26 which is a greenish and muted down red) a classmate made a remark about her alphabet being colored. I normally tuned this girl out because she talked incessantly, but what she said stopped me cold. I asked her to repeat what she had just said, and she paused, hesitant a little embarrassed.well) and told me again, that her alphabet had colors. Oh! We were off and running, comparing our alphabet, (we both had white O's). We agreed and disagreed on certain letters, we disagreed on many, but both of us agreed that our letter O's were white - which I have since read is a common agreement amongst synesthetes. While her numbers were grapheme only, mine were additionally ascribed persona's or sexes. It sounds wacky, but I had at last found someone in the world who spoke "my language." It was incredibly liberating. Our classmates listened in, fascinated, they told us it seemed like we were speaking a different language. And, it really does feel like that. I felt like I'd been marginally normalized at last. My condition, perhaps validated.
She told me what we had was a neurological joining of the senses, a greek word for a condition called "Synesthesia" of "Syneasthesia" and gave me MIT's Richard Cytowic's website. She also told me that Synesthesia was a very "trendy" and coveted condition among artists and creatives. I couldn't imagine wanting to be a synesthete, I mean, I didn't know any other way of being. You didn't think about it - you just were...

I felt like I could exhale at last. Bless Richard Cytowic and his contemporaries for their research. It has been quite an interesting journey. This condition is supposed to be herditary, sometimes skipping generations - or born of a brain seizure or epilepsy. I know of nobody in my family (at least who is talking about it) who shares my condition. I suspect my father may. I sometimes wonder if my mother's reaction was because she herself was - and had never spoken about it. Also, she was a lefty, left handed folks tend to be syns more then right handed folks.I wonder...
I'm a graphic designer, and recently I've seen articles pertaining to Synesthesia in the design community. Are syns more likely to be naturally geared toward the creative field? I don't know, but I know my condition hasn't hurt me any. I plan to read anything I can get my hands on regarding synesthesia. I'm still a newbie to my understanding of Synesthesia, most of my life I didn't acknowledge or know what I had. Thank you researchers, and open-minded scientists. Am looking forward to more of Cytowic's findings and comparisons with other synesthetes.

[Hayley]

Pish posh. Wednesday is periwinkle.

[Yasmeen · Rating 3 out of 5]

Um, excuse you. Wednesday is turquoise.

My immediate and involuntary reaction towards reading the title of this book. I'm synaesthetic-- grapheme/colour and some sight/touch-- and that's mainly why I decided to read it. I'm super interested in synaesthesia, and I'm really curious about why it happens, different types, etc. And Cytowic is most definitely thorough in dealing with every single possible question that could have potentially occurred to me on the subject. I say this with a hint of sarcasm, because it gets to be a little much at times. Which, to be fair, is probably a good thing in terms of it's value as a book intended to impart scientific knowledge. And it might just be me, but I feel like it missed a draft of editing; I'm pretty sure I read identical sentences in a bunch of different chapters though.

For the most part though, it's a lot of fun. The full color is, in this case, a really good idea. And I learned a lot-- brains are weird. The extrapolations in regards to the subjective nature of reality is really good too, and stops the overall thing from being dry and pointless. It's an odd subject, and deserves to be treated as such.

Conclusion: Fringe missed out on a really good potential episode.

[Madeleine]

“Now that’s an actual fun fact!” —Amanda

Such a potent reminder of how we all see the world in different ways. It was interesting to read about other people’s perspectives, and also that Nabokov and his wife Vera had this in common!

Because I barely notice it in my mental landscape, it was both surprising and fun to hear about how other people visualize concepts like letters, numbers, etc. And it makes sense that everyone thinks with multiple senses initially, and it’s only as we grow that we differentiate.

i know it’s different for everyone, but to me, Wednesday is associated with multiple layered colors (not a one-to-one function), but none of them indigo blue! And some letters are also correlated with colors, although I don’t actually physically see them to the extent that some people do. It’s always been something slight—more of a helpful memory device!

Frankly, I’m not sure that this variation between humans is even really possible to study scientifically, and in particular I did find it surprising to read that there’s been no correlation (yet) with prevalence of absolute pitch (still allegedly approx. 1 per 10k, which has always struck me as an outlandish estimate anyway.) because in my mind, the mechanism of identifying musical notes is so closely dependent on colors. I have a cousin who also has both, but unlike him, I think of middle C as a deeply layered gray—not fuchsia.

On that note, I really loved the quote about how none of us actually knows how it truly feels for others perceiving things, whether that’s the experience of the red hue of a stop sign or whether they see the world the same way we do.

[Orsolya · Rating 4 out of 5]

Although it may sound silly, try to imagine life if you saw letters as colored. How about seeing shapes when you tasted foods? Consider personifying the day of the week or numbers. Even, seeing colors when hearing music. Sound like an acid trip? It’s not. It is very real and is called synesthesia. More people experience these triggered and inter-connected senses than realized (Stevie Wonder! Eddie Van Halen!). Richard E, Cytowic MD and David M. Eagleman PhD explore this growing field of study in, “Wednesday is Indigo Blue: Discovering the Brain of Synesthesia”.

The aim of “Wednesday is Indigo Blue” isn’t necessarily to prove anything as the study of synesthesia has hardly been tapped. Despite this unfortunate fact, Cytowic and Eagleman are well-versed in the field and introduce the reader to synesthesia, its various forms, experimental results, and the current state of exploration. This is supplemented by many examples of actual synesthetes, illustrations, charts, graphs, etc. Cytowic and Eagleman’s passion and intelligence shine through which not only entices the reader but educates at the same time. The topic is both fascinating and captivating.

With that being said, “Wednesday is Indigo Blue” is not necessarily for an average reader seeking a summarized look at synesthesia. The text is detailed and oftentimes is very overwhelming with its scientific jargon and too-fast pace which assumes the reader perfectly understand what is being described. This can cause a loss of attention and confusion.

Other issues lay within the format of “Wednesday is Indigo Blue”. Each chapter contains too much information and is a journey in many directions; making subjects difficult to retain. On top of this, there is a lot of back-peddling and repetition. Although containing some dated test results; “Wednesday is Indigo Blue” is a strong piece if searching for a ‘history of’ stylized look at synesthesia. However, if looking for specific answers or a thesis; you won’t find it here.

This bleeds into the problem that Cytowic and Eagleman often draw the reader in with specific discussions only to abruptly announce that more information doesn’t exist in the field to express the idea further. In other cases, the authors constantly mention that they will continue the topic in another area or chapter. This breaks reader focus and results in “Wednesday is Indigo Blue” reading more like research notes than a smooth, cohesive text.

All of these complaints aside, “Wednesday is Indigo Blue” is a great thorough look at synesthesia. The reader is encouraged to turn the pages and to do his/her own research. Yes, it may be slightly over the reader’s head but that is better than being too dummied down and boring like some other neuroscience pieces. Cytowic and Eagleman present a good ratio of scholarly text to a well-written article of interest.

Halfway through, “Wednesday is Indigo Blue” changes its focus from the types of synesthesia to how it effects art (and vice versa), the possible intricacies of the brain causing it, similar behaviors, etc. In this way, Cytowic and Eagleman open up the world of synesthesia to demonstrate the bigger picture/ impact. The only problem is that many of the statements are far-fetched and ‘stretching’ the connective theories.

“Wednesday is Indigo Blue” wraps up with an illuminating look at the possible future research routes of synesthesia. Granted, the text if dated and ‘behind’ but the authors still conclude the book on a strong key. A notes and bibliography follow for readers who double as fact-checkers.

Despite its mentioned pitfalls; “Wednesday is Indigo Blue” is an impressive look into synesthesia as both an introduction and passionate persuasion into the field. Although the average reader may find some bits to be overwhelming or too scholarly; Cytowic and Eagleman will satisfy all who are interested in this complex brain perception.

[Jocelyn · Rating 5 out of 5]

I feel so much less strange and alone after reading this book. I highly recommend it to any synesthete or anyone who wants to show some love and affection for the synesthetes in your life (and odds are there are several!).

The book starts out describing the types of synesthesia and how people realize they have it. I read the middle chapters quickly, but chapters 9 and 10 get into the theories of what cause synesthesia and experiments that support or argue against different hypotheses, as well as related discoveries and suggestions for future research. Fascinating stuff, all of it.

[Samantha Glasser]

Wednesday is orange-y.

I never came across objections to my synesthesia as a kid. If anything it made me love music, which gave me goosebumps when I loved it (and when it was so bad it made me uncomfortable too), and burst and morphed into a phantasmagoria of color in my mind like an old PC screen saver. It helped me remember things more definitely. I didn't even recognize it as being different until I was an adult. It became troublesome when my husband and I were trying to name our sons, and I kept objecting to certain names because the colors weren't right.

[Hillary · Rating 4 out of 5]

I love that this is a thorough overview of synesthsia from the scientist who kicked off research for this condition. I loved getting to read about myself and say, "Oh, that's what I do! Now that makes sense!"

[ɯɐɔ]

I'm not a grapheme syn, but a music/sound-color/image one. It depends on the sound and depends on the area I'm in. If I'm in my room, for example, and I hear certain music, then close my eyes, a bright fuchsia pops up. This happens for most words, and isn't really a part of being a syn. However, I am an avid artist and musician, so during the time that I express my creativity, you can "see" my synesthesia. Music becomes a flurry of random (yet practical, to me) lines, dots, and squiggles. I have not tried poetry yet, but I have words and sentences, and those results are odd. During Symphony, I play clarinet and thus sit in the middle of things, and can almost feel the music. It's hard to explain, but it's like the music is a ribbon cut into many parts, and the low brass are usually dark blue, while trumpets are red and clarinets are purple. Flutes are grey, saxophones are orange, and percussion is usually a sky blue.

As I write this, my head is throbbing a tad, and I wonder if that is what it is like when other syns use their "ability". Are there any other music-color syns out there on GR?

All in all, I need to read this book. ;D

[Cheri · Rating 5 out of 5]

"Reality is not one size fits all." That's the take-home message from this fascinating book by two neuroscientists who study synesthesia. The stories of people who see music, taste shapes, or sense a color with every number fill the pages, but it's also a story of how researchers in the field have honed in on what's happening in the brain with a wide range of cross-sense perceptions. It turns out that this kind of experience, to varying degrees, is much more common than previously believed, and that perception of cross-sensory similarities may be innate. Particularly interesting to me were the discussion of the cross-cultural similarity of sensory metaphors and the explanation of synesthetic perceptions that may be reported as religious experience.

[Renske · Rating 4 out of 5]

Obviously written by a scientist, this book is not a page turner but very informative and sometimes also speculative. The book starts with many examples of synesthesia and explanation follows more towards the end. I wonder how it must be to read this book without having any form of synesthesia. For me chapter 5 was more interesting than the other chapters describing examples of synesthesia, as it relates to my own type of synesthesia. I am very curious what insights further research might bring!

[Derek Walsh · Rating 3 out of 5]

A fascinating study of the phenomenon of synesthesia, this book is exceptionally thorough, detailing all the various kinds of synesthesia, their relative frequency, possible explanations and suggested further studies. A little dry in places as it is essentially a textbook, but still very interesting.

[Mei · Rating 5 out of 5]

My Wednesday is red....and it's number 4, since my red is 4.

[Cheryl · Rating 4 out of 5]

Thorough, and scientific, but still accessible. I didn't read every word, as I am only curious, and this is not directly relevant in my corner of the world, but I certainly ache for those who suffer the prejudices of either being thought mad or overly imaginative. And I rejoice for those, apparently the majority, who have learned to love this special talent that they have.

And according to the authors, it is a talent. Synesthetes are, the reader is informed, rather likely to be more creative, to have better memories, even to be more intelligent. The flaw in the book is that sometimes those claims are made in absolute terms, but the research explored indicates that there are only tendencies and likelihoods.

There are many interesting bits:

Sean Day, smell/taste -> color, enjoys foods that evoke harmonic or complementary or monochromatic color palettes: "... baked chicken with a scoop of vanilla ice cream topped with orange juice concentrate."

"We need to point out an important distinction that neuroscience makes between feelings and emotion because the two are not identical.... Emotion is unlearned behavior, an unfelt automatic script playing itself out, whereas feeling is the mental readout of emotional scripts. The unlearned reactions of emotion always change the body's physical state.... Emotional scripts play out unconsciously until feeling enters in: only then does the mental readout let us take stock and, if we are emotionally intelligent, make a connection between what we feel and what triggered it."

I appreciate that the distinction is made between colors of light and colors of pigment. I don't understand it all though my son has tried to explain it, but I have noticed that the 'primary' colors of the color wheel that we learn in grade school are not the 'primary' colors on a printer!

The authors also make it clear that artists can metaphorically represent cross or linked modality. But that does not mean that Georgia O'Keeffe was a synesthete. Wassily Kadinsky, otoh, was... and his work is referenced & explored here. (But not included, we have to google it.)

Many synesthetes have difficulty with arithmetic. Many also have finger agnosia. To test: ".... The subject closes his or her eyes and places the hands palm down on the table. The examiner then touches various combinations of two fingers while asking "how many" fingers are between the ones touched. A surprising number of synesthetes make errors when doing this sensory task, thus implicating their angular gyrus."

Anyway, I do see that reviewers who are synesthetes rated this book well, and I do recommend it.

[Bob · Rating 4 out of 5]

Sixteen years ago, while I was student teaching, I first learned of synesthesia - one of my students had grapheme - color (letters/numbers - color) synesthesia. I was astonished: he could see the number 2 typed on a page full of 5s, because they were different colors. I began learning of other synesthetes (it won't surprise anyone to learn of great musicians or visual artists or writers who have this condition and express it through their art), and reading about the experience (for example, Born on a Blue Day).

This book, published in 2009, is the work of one of the foremost researchers and scholars of synesthesia, and it dives deep into both the condition (which can be manifested in as many as five or six different crossed senses in a single individual), and the research that had been done to that date on the neural networks that create the condition. So much remains to be understood, but Cytowic's work has established the fundamentals of synesthesia and its development in individuals, from babies to elderly adults (the genetic component makes it commonly traceable in families).

Although some of the science is slightly over the head of this non-scientist, the research and conclusions are presented in language and order as understandable as possible, and I found the book overall both enlightening and amazing. I'm sure I'll read more, particularly by and about the artists whose works have been shaped by their synesthesia - like Kandinsky, or Stevie Wonder (yes, blind people can be synesthetes), or Nabokov (whose son wrote the afterword to this edition).

[Kathleen · Rating 5 out of 5]

This book is a wonderful resource if you are curious about synesthesia in any way, shape or form. It covers so much detail and gives many personal examples and experiences. It truly opened my eyes to the many forms synesthesia can take, and how it affects every person individually. It's a lot to take in, honestly, and in order to get a proper reading experience I needed to be in a quiet place with no external distractions. If you are looking for a synesthesia "Bible" I would say this is definitely one of them.

Some of my favorite passages from the book:

"Erica's senses and concepts are open to each other, flowing and merging like weather streams."

"They gave cosmic interpretations instead of straight forward descriptions, poetically embroidering their sensory experience."

"We possess about 1,000 olfactory receptors, the result being that aroma sensations are far more diverse than taste sensations."

"Pain and pleasure sensations evoke visual/spatial perceptions which are also in color. When I kissed my boyfriend I saw orange sherbet foam."

[Riguelis · Rating 4 out of 5]

I don't have synesthesia nor do I know someone personally with it, but still I found the book a worth read.

Synesthesia is a very exciting phenomenon, with so many particularities and individual differences that it may strike you at first as a very hard field of study and with little practical applications and/or a quite small set of implications about how the brain works. Also, if you are not a synesthete, you won't feel as attracted to the topic as someone who is.

Nonetheless, this books tries his best to offer a complete picture of synesthesia in scientific terms, with interesting hypotheses and ideas and abundant examples. Definitely, it shows how different each of us are and how our experience of the world can be fascinatingly unique.

Beware, this book won't explain anything about the genetics of synesthesia, it will merely mention some speculative ideas and a few facts about what researches know so far💡

[Riana · Rating 5 out of 5]

Synaesthesia is a baffling phenomena that surprisingly few people are familiar with. This book is a great starting point for people who want to know more about this field, especially from an academic vantage point. I seldom read textbooks cover to cover, or review them when I do, but this was the most fascinating and inspirational academic book I've gotten my hands on in the past five years!

Richard Cytowic and David Eagleman give a thorough account of the history and current situation of synaesthesia in the academic world. They share information from a vast array of sources and are honest about the many questions still left unanswered despite years of research.

This is a great resource if you want to get an in-depth introduction into the world of synaesthesia. I borrowed this copy from my university library, but I am definitely acquiring my own copy for my synaesthesia studies ahead!

[Carmen Kane · Rating 4 out of 5]

I'll admit I only skimmed the chapters that weren't applicable to us. I found it interesting that synesthesia is thought to be essentially a crossover or extra connections, the same theory as Sensory Processing Disorder and some ADHD symptoms. The theory is that people are actually dealing with an overload of input which makes it harder to process at times. I also latched on to the fact that it 'expresses' itself in different ways. In our family there are multiple people with separate learning differences. The neurologist feels it is a genetic difference manifesting in different ways, but it all comes from the same part of the brain. I find it all very fascinating! I found the book very interesting and informative.

[River · Rating 4 out of 5]

This is much more interesting than I initially thought. As a nonsynesthete, I found myself craving every kind of synesthesia, especially grapheme-colour and phonetic-colour (as well as music). Emotionally mediated synesthesia is also fascinating! This book gets four stars partially because of my jealousy—I WANT to have it ever since I knew it was real (in grade six/seven probably). It's also a mystery that since 4% of people have synesthesia, why don't I know any???? Seriously. Recently someone I know said "I have synesthesia," which suddenly evoked my memory about the synesthesia book I LOVED, and I subsequently did a bunch of research on it. So, thanks to that person, I promise I will bombard you with questions.

[Clicky Steve · Rating 4 out of 5]

This book is about synaesthesia - the phenomenon where individuals experience multiple sensations in response to a single stimulus. For example… associating a colour or personality with a number, letter, or word. This is something that I have, and only realised it wasn’t ‘neuro-typical’ after reading about a character in a novel who had the same thing. This particular book delves into the topic from a scientific position, outlining various studies that have been done, the state of research, and the outcomes/observations. It took me a while to get through as a result, as despite being very interesting and readable, it was also fairly dense. I am glad this exists though, as there aren’t too many explanations or accessible texts which dive as deeply as this one.

[Kevin K · Rating 3 out of 5]

This is a thorough overview of synesthesia and related research, but the field is more trivial and boring than I expected. The main focus of this book is people who associate colors with letters and numbers. My interest is more the extreme forms of sensory crossover like Shereshevsky in Luria's The Mind of a Mnemonist, or Lidell Simpson (who hears color), or Michael Watson (who has bizarre tactile and shape-like responses to tastes), or the sort of synesthesia brought on by powerful hallucinogenic drugs. This was a poor source on those cases.

[Lindsey Duncan · Rating 4 out of 5]

This is an in-depth exploration of synesthesia from a scientific perspective, pondering everything from its origins to its manifestations to unusual side effects. Though it is a dense book tackling neurological theories, the author has done a good job of making it comprehensible to the attentive layperson, and the many diagrams and illustrations of concepts throughout are valuable. Perhaps this book spends a bit too much time on what science doesn't yet know (or didn't, at the time of writing), but otherwise, it's an excellent read, though it definitely requires full brainpower.

[Moriah · Rating 3 out of 5]

I liked all the stories of real people and interesting details about how synesthesia works. I didn't like the focus on an assumed synesthesia gene - it wasn't clear at first that this gene is simply anticipated and not already verified. The author could have done better in more clearly distinguishing his theories from what completed research has demonstrated.
This book is a little dense, not exact light reading. But it's interesting information; so for anyone is fascinated by unusual phenomena and quirks of humanity, I advise reading this book.

[Jukka Häkkinen · Rating 2 out of 5]

Kattava katsaus synestesiaan, kaikki mahdollinen taiteesta neurotieteeseen on käsitelty. Kirja on kuitenkin rakenteellisesti sekava, tätä olisi pitänyt editoida ja organisoida vielä pari kierrosta. Nykymuodossa asiasta toiseen hypähtely ja samojen asioiden toistuva käsittely tekevät kirjasta uuvuttavan lukukokemuksen.

[Lily · Rating 4 out of 5]

This book was very educational. I have been interested in Synesthesia ever since I read A Mango Shaped Space by Wendy Mass when I was younger. This book definitely make the condition a lot easier to understand with analogies and examples. There were accounts and interviews of Synesthetes, as well as illustrations to better explain the text.

[Andy Plonka · Rating 3 out of 5]

This book requires some persistence for the reader who is not familiar with synesthesia since the condition takes many forms as it is not one specific condition. The most widely publicized form is seeing colors as numbers or letters. I have not been enlightened so much as confused by the various permutations of this condition and their authenticity.

[Rebecca · Rating 4 out of 5]

Wednesday is orange.
I learnt about types of synaesthesia I didn't know existed, but I particularly loved that so many people report the same someone-told-me-I-was-crazy when mentioning it at a young age that I experienced.

[Julie · Rating 3 out of 5]

This publication of sensory-mixing neuroscience spends a great deal of time on the relationship between letter/sound/experience with color/texture. I was hoping for more data on emotional attribution and anthropomorphism.
This was a good start... I will be looking for more.

[Carolyn · Rating 5 out of 5]

This book is clearly written, and describes the different types of synesthesia very well. It provides good data on what synesthesia is and is not.