Let me start off by saying that it takes a lot for me to cry (or laugh) over a book. As in, it rarely happens and I don't even know if I can remember the last book that elicited that emotion. However last night when I finished Die, I was actually sobbing like a fool (seriously, it was kind of embarassing). The novel follows Tessa, a 15 year old girl with a terminal illness as she attempts to get the most out of life before the cancer gets her. She constructs a list of 10 things she must get done and the beauty of this is that they're things that anyone would want to do - fall in love, be famous, have sex, etc. What makes this novel so heartbreaking is not Tessa's deterioration, but seeing how her illness has affected her family and friends. Even though you know how the book ends, it's still a shock.
Downham's novel is targeted and marketed to the Young Adult demographic, but honestly, I think anyone would enjoy it. Just be prepared - Terms of Endearment and Beaches have nothing on this book.