Books that are about "Something"

Last week I finished a book called Paper Towns by John Green.  He is a writer who particularly writes for high school guys.  That's a generalization, but anyway.  He is one of the hot names in young adult fiction right now. Paper Towns was his second or third book, I forget.  The main thing, though, is that it grabbed me and wouldn't let go.  I'm not sure exactly what it was, but I found myself identifying with the characters, Quentin in particular.  I don't want to recap the story; click here for a summary. What I wanted to share was that the story stayed with me.  I kept finding myself thinking about it.  It seemed bigger than it was, like it was about "Something".  The last time I had this sense after reading a book, I had just finished the Time Traveler's Wife.  Read either or both of them.  They are well worth the time.  And let me know if you figure out what they are REALLY about.