The Catcher in the Rye is the ALLTIME Classic teen book. OK, Holden Caulfield is rich and negative. His time in New York is journey into maturity. Read it. Don't shoot anybody with the book in your pocket or I will revoke your library card!
The Book Thief, Markus Zusak, is a historical fiction novel set in Nazi Germany. Told from the perspective of a personified version of Death, The Book Thief is a outstanding and unique story that shows what it's like to be alone and afraid.
The Boy in the Striped Pajamas, by John Boyne (teen fiction). Bored and lonely after his family moves from Berlin to a place called "Out-With" in Bruno, the son of a Nazi officer, befriends a boy in striped pajamas who lives behind a wire fence.