This isn't a review. Not yet, because I'll need some time to digest all of this.
It's not perfect, but nobody was expecting perfection: it's a great ending to the saga, nonetheless.
I didn't enjoy everything about it, so here are its flaws: too many scenes reminded me of what I had already read in his previous books. I think he couldn't help but imitate himself, causing many scenes to trigger a sense of deja-vu. He definitely overdid, but it couldn't have been otherwise in building such a massive architecture. The first thing that comes tomind to describe this book is massive: its "architecture " resembles Zafon's beloved cathedrals and gothic labyrinths.

You know everything that's happened in the previous three books, in whatever order you read them? Well, those three books only laid the groundwork: this last story raises itself from those groundworks and grows higher than anyone could predict.