I just finished Flowers for Algernon. It is, I think, the most emotionally crushing book I've ever read. I've never cried this hard at the end of a book. The closest to this was at the end of A Prayer for Owen Meany. My God, I can't even think about this book without getting verklempt. I think, for me, the hardest part, is realizing he'd hit these magnificent transcendent highs, and then to be denied even the memory of them, left only with a hint, a vague whisper. To meet God, and then forget. This is a true novel of ultimate loss.