An Abundance of Katherines

An Abundance of Katherines is a young adult novel by John Green, published in 2006. Colin Singleton, a former child prodigy, has been dumped by nineteen girlfriends, all named Katherine. After the latest breakup, he sets off on a road trip with his friend Hassan and ends up in small-town Tennessee. There Colin tries to prove a mathematical theorem predicting the course of relationships, and learns about friendship and what it means to matter.