The Time Traveler's Wife, Audrey Niffenbegger.

"Okay," I say, "let's see. The choices we're working with here are a block universe, where past, present and future all coexist simultaneously and everything has already happened; chaos, where anything can happen and nothing can be predicted because we can't know all the variables; and a Christian universe in which God made everything and it's all here for a purpose but we have free will anyway. Right?"

Clare wiggles her toes at me. "I guess."

"And what do you vote for?"

Clare is silent. Her pragmatism and her romantic feelings about Jesus and Mary are, at thirteen, almost equally balaned. A year ago she would have said God without hesitationl In ten years she will vote for determinism, and ten years after that Clare will believe that the universe is arbitrary, that if God exists he does not hear our prayers, that cause and effect are inescapable and brutal, but meaningless.

Niffenbegger is not a great writer, but she is a great plotter. This is one of those books you have to read twice, the first time to understand the layout, and the second time to pick up all the references that were dropped the first time --- passages in Henry/Clare's lives that didn't make sense the first time round because you were getting it out of order.

Highly recommended!