The Perks of Being a Wallflower
by stephen chbosky
Written in letter form. But you don't know who the main character, Charlie, is writing to, or if that is even his real name. I like how the story unfolds over the course of his first year at high school. You become a part of his strange world, knowing his friends, his family, and mostly his thoughts...his real thoughts. He doesn't hold anything back. The things he thinks are completely bizarre, but absolutely humorous. And yet, at the same time he'll also make you feel very sad. But mostly it makes you long for those perfect days with your friends, when everything is good, and you feel "infinite".
Definitely read this book.