Ex Libris by Ross King

This is a book about books, a bookdealer, with a cup of mystery, a dash of intrigue, and one very important book. Labyrinths mundi, the Labyrinth of the World, with the ex libris of its former owner, Sir Ambrose Marchemont, in the front, is lost. Lady Marchemont, Sir Ambrose's widow, the aged proprietor of Nonsuch Books called Isaac Inchbold, and the girl from the past, Emilia, wander through a maze of a larger, unexposed story that they do not recognize.

They "stumble in ignorance along its dark arteries, stumbling through blind passages and secret chambers in which, even years later, they still find themselves searching in vain for a clue."

"...her head bent over the volumes, blowing dust from the bindings or tracing her fingertips across their surfaces like someone exploring the curves of a loved ones face. Once she had even raised one of the books to her lips and, closing her eyes, sniffed at it as one would at a rose."

"It is easier to find a labyrinth...than a guiding path. Yet every labyrinth is a circle that begins where it ends,... and ends where it begins."