4.5 stars. This book is extraordinary. In a bloated genre, Ultraviolet is a fresh and unique story that seamlessly weaves internal and external conflict in a stunning genre-blending work.I've always been intrigued by synesthesia, and Alison, the protagonist, is sort of an ultra-synesthete. Anderson does a masterful job at portraying the world as Alison experiences it--the sensory descriptions were perfectly organic but also fascinating.I will say that I'm unsure what to think about Anderson's portrayal of mental illness and Pine Hills, the adolescent treatment facility where Alison finds herself, and my uncertainty is a large part of what caused me to dock the book half a star. I would really love to see a review of this book from someone who has experience with mental illness.For those who've read the book: Something that is driving me crazy is the fact that Sanjay's spot-on description of the alien transmitter was never addressed. Clearly his paranoid delusions had some basis in fact. At the end, I kept waiting for Alison to bust out the scrap of paper she had tucked into her jeans and have it actually be a phrase in Faraday's language. That Alison never even thinks about the fact that Sanjay was right on a lot of things is another reason I docked the book. I really, really hope this is brought up in the sequel (set for release in 2013).Like some other reviews I've seen, I was really excited that the author actually went there with the novel. For a while, I was scared that she would do a cop-out, "Oh, Alison actually just witnessed the traumatic death of Tori and this is her mind's way of coping" route, or worse, the "Was she crazy all along, or did this really happen the way she thinks?" route (*glares at Justine Larbalestier*), but she didn't, and I was so happy.This book is definitely one of the must-read YA novels of 2011.