What I Liked
This is definitely a unique story. I read a tweet somewhere that said John Green writes like he rolls a die to decide something like, "My protagonist will be a child prodigy who only dates girls named Katherine and whose best friend is an overweight Muslim kid who is obsessed with Judge Judy. Really. That's what the book is about.

What I Didn't Like
The plot of An Abundance of Katherines isn't super catchy. I found myself getting bored, and even though it was a short book, I read it in four, five, six sittings instead of my usual one. Maybe I'm just not a big math fan.

But I didn't get the theorem. I didn't get the point of Colin dating all of those Katherines. I didn't get the characters and their weird jokes (fugger, switching randomly to different languages, etc). And I did not get the sheer quirkiness of the characters as being realistic. Yes, everyone has their own quirks, but those quirks don't define who we are. Colin's entire identity lied in his insane intelligence and his heartbroken self and everything about Hassan was his humor and fatness. It just didn't flow for me.