This book hits a few loves with me. First off, the narration structure. The book is based around the legend of Prester John, a medieval European legend of a priest-king who ruled over a land of legend off somewhere in the east. In 1699, a group, lead by a Brother Hiob, sets out to find traces of his kingdom, and come across a hamlet with a strange woman, who tells them that Prester John is gone, and shows them to a tree with books for fruit, and tells the head of the expedition he can pick three. The narrative is interwoven from those three books and Hiob's comments as he fights the decay of the books -- which, being fruit, don't last long once picked -- to record them and send them back to Europe.
( The three interwoven narratives are John's own accounts of his travels, a memoir of Hagia, one of the locals who eventually ends up as John's queen, and a book of stories, which do a lot to explain how the country of Pentexore came into being and fill in the history that Hagia knows and John never asks about. )