I do not know where to start in talking about this book.
I suppose I should start with the fact that I choked up in every single on of Hagia's sections, and half of Imtithal's. This is partly because I am a sap, but mostly because this book (and this trilogy, given the foreshadowing) is about a fall from paradise, about the elves going off to the Grey Havens, about the horrible inevitableness of the change you don't see coming. And that atmosphere hangs over every passage of those two narratives, infusing them with an exquisite sense of loss.
Three narratives, actually, because Hiob's framing narrative is also imbued with that grief, though at a remove.
There are four narratives, by the way -- the three previously mentioned and that of John the Priest. That complexity of structure is typical of Valente's novels (at least the four I have now read); she weaves together disparate narratives better than any author I have ever read, ignoring linearity in favor of thematic resonance. So Hiob says "I have boys to scribed for me now -- for I have often and in secret thought that it is boys' work, to copy and not to compose, to parrot, and not to proclaim" and four pages later Hagia writes "I have been all my life a scribe. . . But in the end. . . I attempt, with clumsy but earnest need, to compose and not to copy. . ." Characters echo one anothers' thoughts without knowing, and their actions are mirrored or reversed to throw light on the sorts of people they are.
This is the sort of book that rewards careful reading, and punishes any lack of attention or attempt to skim.
John's narrative, at first, does not seem to fit with the other three. It is the most chronological, mostly confining itself to whatever events it is relating rather than musing on what came later (though John does do a little of this sort of foreshadowing); it is also the most surreal, and the first section when he is adrift on the sea of sand is downright hard to figure out, because we don't yet have enough knowledge of the world to know what is real and what is metaphor. But that discordant note is a very carefully measured choice on Valente's part.
There is a passage in Lois McMaster Bujold's THE CURSE OF CHALION that seems appropriate, so I will quote it here:
"You have to make a cup of yourself, to receive that pouring out [necessary to becoming a saint]. You are a sword. You were always a sword. Like your mother and your daughter, too -- steel spines run in the women of your family. I realize now why I never saw saints, before. The world does not crash upon their wills like waves upon a rock, or part around them like the wake of a ship. Instead they are supple, and swim through the world as silently as fishes."
John is just such a sword. He is the catalyst, the thing that, when added to Hagia's delicately balanced world, changes the world rather than being changed itself. That's why when he finally is mirrored it's by Thomas, another Christian who stumbled into paradise, with vastly different results.
And Hagia is. . . absolutely the most perfect challenge her world casts against John. The book is incredibly sensual -- far more sensual than PALIMPSEST, which was all about sex. Each of the men of the Church is confronted with the world of the body he thought he left behind: Thomas by Imtithal's physical affection; Hiob by the fragrant, liquid rot that worked against him in his task of copying; and John by Hagia, with her eyes where her nipples should be, at the tips of abundant breasts, and totally comfortable in that body. The tension in the book comes from those challenges, even though we already know who ends up the victor.
To bring a long rambling squee to the point, every moment of this novel is perfectly constructed, every choice deliberately calculated to further the story being told. Because of this (not despite it) it is deeply moving. The best thing I read last year was Valente's two-volume THE ORPHAN'S TALES; so far this year, it is definitely THE HABITATION OF THE BLESSED.