Colin Singleton is a semi-burnt-out child prodigy who spends a summer coming of age as he develops a theorem to account for the fact that he's been dumped by nineteen girls, all named Katherine. Includes an appendix explaining functions and graphs, written by real-life mathematician Daniel Biss, a friend of the author. Biss mentions the work of psychologist John Gottman and mathematician James Murray on the mathematics of marriage.

John Green is one of my favorite young adult writers and I really like the fact that he asked Daniel Biss (who was a Clay Research Fellow at the time) to write an appendix about the math.

I love the book, but considering it a piece of mathematical fiction is an overstatement.

Math is definitely there but I just found it to be annoying the entire time. It's just nonsense and, overall, sends the wrong message about what math is, to be honest.