Colin Singleton just graduated from high school and got dumped by a girl named Katherine for the nineteenth time. Ever since he began dating, his girlfriends have have only been named Katherine, and it has to be spelled exactly like that, and she can't go by a nickname like Kat or anything. But weird dating type aside, Colin is no ordinary boy. He is a prodigy, and has always been super-smart. He tries to read 400 pages a day, and he learns facts like crazy. Unfortunately, prodigies are not so cool forever, and Colin is beginning to figure this out for himself. If you're a genius, you invent things, and you're brilliant into your adult life. But prodigies...well, Colin feels like they never do anything really special. You get to be that ten-year-old who knows everything, but by the time you hit college, you're just like everyone else, and it sucks, since for your whole childhood you were called special and brilliant, and now...now you're not. And to make matters worse, this most recent Katherine who dumped him...well, he was actually in love with her. He knew that it was more than just a crush, more than the feelings he had for Katherines throughout elementary school, middle school, and the early years of high school. He is heartbroken, depressed, and feels useless. So when his friend Hassan Harbish shows up at his house shortly after the terrible dumping and offers to take Colin on a road trip to dispel his misery and perhaps find a new purpose, Colin readily agrees. The boys soon head out of their hometown of Chicago and find themselves in Gutshot, Tennessee, a little town that claims to contain the grave of Archduke Franz Ferdinand. Colin and Hassan meet a girl named Lindsey Lee Wells, whose mom, Hollis, offers the boys the job of interviewing Gutshot residents to compile an oral history, and in exchange, she will pay them $500 per week and give them room and board at her house. Between interviewing, Colin is trying to come up with a formula he calls the Theorem of Underlying Katherine Predictability, which is supposed to show the progression of a relationship, and could also be used, Colin believes, to predict the future. At the same time, he's trying to convince Hassan to go to college. His friend has "taken a year off" and that one year looks like it may turn into two if Hassan isn't careful. While spending the summer in Gutshot, Colin discovers many things about Katherines, the Theorem, being a nearly-former prodigy, and the way he loves.
Slight spoiler
One of my favorite parts of the book was the creation of Lindsey. In so many YA books--even the really good ones--the love interest is constantly being described. Their hair, their eyes, their height, their width, their skin, their clothes, oh-they're-so-attractive, etc. But Lindsey Lee Wells was pretty slim on description. When you first meet her, it says she has mahogany hair, but that's as far as it goes. Sure, a few words are sometimes spent describing her clothes in vague terms, but it's very natural and fits well into the rhythm of the story without seeming like an ostentatious description of the girlfriend. Perhaps it helps that Lindsey is not single at the beginning of the story, and she is not a Katherine, so why would Colin waste time thinking about her romantically, etc. You don't know what color Lindsey's eyes are, if she's tall or short, fat or thin, pale or dark. Maybe this is just a reflection of Colin's character and how dorky he is, but I think it's deliberate in a very different way.
End of the slight spoiler.
There were a few things that I found really, really annoying about this book, though, mostly repetition of words like kafir and Jew-fro. But that was a pretty small thing.
In short, I would recommend this book to most people who like YA realistic fiction and the kinds of things that Colin likes, such as anagrams and math. I guess even if you don't like those things, if Hassan is your sort of person (I know I don't say a lot about him here; you can always research the character elsewhere), it could still be a good book. Not John Green's best, but unless he's hiding something away because it sold so badly, I don't think he's written a truly unpopular novel.