No spoilers, browncoats.
The format was interesting, told backwards though time as Book got younger and younger, causality reversed. But...
I don't want to say much more, but I'll just note that my imaginary life for Book was very different, and the reveal on these sorts of mysteries is always bound to disappoint. We can imagine whole spinning, contradictory plots that don't fold into the deck of cards of a life, one card on the other, the ante on the table, the dealer forced to claim the tall card.
The hand never plays like I want it to. It's not the fault of the hand.