This is Arya's last day in Harrenhal (ACoK)
I'll begin with the most important passage. Its significance is not clear to me. I would welcome more insight. Forgive me if you think my comments seem to stray at some points.
Recall that Arya serves as Roose's page in Harrenhal.
She placed the food at his elbow and did as he bid her, filling the room with flickering light and the scent of cloves. Bolton turned a few more pages with his finger, then closed the book and placed it carefully in the fire. He watched the flames consume it, pale eyes shining with reflected light. The old dry leather went up with a whoosh, and the yellow pages stirred as they burned, as if some ghost were reading them.
I get from this passage that
1) Roose has been reading for some time (he notices it gets dark, as if he had been absorbed by the book).
2) The comment "It grows gloomy here." might reflect what he is reading.
3) Roose does not read the book completely.
4) He burns the book calmly and deliberately.
I have a few little things to add. Curiously, the same day, in the same hearth, Arya had burnt Fat Walda's letter.
In the pre-printing era a book is a treasure, so burning one is significant. The light in Roose's eyes (usually so inexpressive), the scent of cloves (an essential ingredient of incense, candles with cloves are used in certain pseudo-magical rituals in the real world) and the evocation of the ghost make me think of a kind of ceremony, perhaps a mystical sacrifice of the book, if such a thing makes sense.
But what book could it possibly be?
Here is an earlier scene (still the same day)
Note that the candles (of the solar) have burnt completely. Roose stays awake late apparently busy with writing and reading. Curious activity for a warlord. Note also the armload of soiled clothing. What did Roose study in Harrenhal? Who did he write to?
The scene happened on the day Roose decided to betray the Starks. Here is a scene from still earlier the same day.
At that moment, the Freys attempt to convince Roose that the war is lost. But the news that Robb had married a Westerling would came only later that day, just after has Roose decided to go for a wolf hunt, signifying to us the betrayal of the Starks.
Let's turn to the false maester Qyburn. The necromancer is clearly part of Roose's inner circle since he attends the conversation with the Freys. He is in charge of the leeching and of the ravens. Roose's leeching habit predates the encounter with Qyburn (*). It's never explained how Qyburn could have gained Roose's trust so quickly.
Here is how I attempt to reconstruct what happened: Qyburn had visited Harrenhal's library as soon as he got in with the Bloody Mummers. He made some findings of great interest (the book) that he passed to the new lord, Roose. Thus he gained Lord Bolton's trust and became Roose's closest advisor (do we know of any other advisor of Roose, besides, and even that is improbable, Walton Steelshanks?).
Roose rewarded Qyburn handsomely, by sending him to King's Landing as Jaime's savior, paving the way for Qyburn's rise in King's Landing, while the other Brave Companions were abandoned to a doomed occupation of Harrenhal. Qyburn did not start his carreer in necromancy in King's Landing. What did he do in Harrenhal? Did he join the Brave Companions to have access to Harrenhal?
There are good reasons to believe that Harrenhal holds secrets of interest for the North. Consider Old Nan's stories.
Among the former owners of Harrenhal,
“Lady Shiera does. Lord Bloodraven’s paramour. She bathes in blood to keep her beauty.
Once thing has consistently struck observers of Lord Bolton: his extraordinarily youthful appearance (Reek, ADwD).
It's time to offer a speculation: Roose Bolton is a sorcerer. Some Dark Arts, which might include the leeching, are preserving his youth.
(*) Note about leeching: there seems to be two kind of leeches: the black ones and the translucent ones, both are appropriate for leeching humans. It seems that Roose switched from the black variety to the larger translucent type after meeting Qyburn. Significance?
Edited by Bran Vras, 02 March 2012 - 06:32 PM.