In the Kite Runner how does Amir's relationship with the past contribute to the meaning of the overall book?

In many ways, one could argue that Amir's relationship
with the past is what makes up the entire novel and is driving the action.  As Amir
recounts his entire life was based around trying to deal with that one moment during his
childhood.  Of course there were other things he had to work out about his relationship
with his father and Hassan but he was always looking
back.

And he makes it clear that this working out of the
past, this force driving him from the past is what made him who he was and what
determined the depth and the breadth of his relationships and his vision of
himself.