The Year of Secret Assignments by Jaclyn Moriarty

This epistolary (written in letters) novel had a great plot, interesting characters, and a really neat style. The Ashbury-Brookfeild Pen Friend Program was meant to unite the two rival schools, but in actually it stirs up more trouble. Cassie, Lydia, and Em are the three Ashbury girls. Their pen friends from Brookfeild are a boy who calls himself Matthew Dunlop, Seb (short for Sebastian), and Charley. By the end of the first term, each pair of pen friends plan to meet up. Cassie’s pen friend turns out to be nasty and crushes her spirit. Em decides to teach Charley how to Get the Girl, but secretly she really likes him. Lydia doesn’t know how to feel about Seb, but they form a friendship that starts off with secret assignments for each other, but as time goes on, they become really close.  By the end of the book, all of the main characters have grown and changed, learning about how to be themselves along the way.