The Two Towers

The second volume of the novel The Lord of the Rings, The Two Towers, was given to Harry Dresden by the archangel Uriel towards the end of Small Favor.

Small Favor
The copy was an old and battered paperback, folded and left behind in the hospital chapel on a janitor's cart for Harry to find. One page was marked by a dog-ear, on which a section of dialogue was underlined with pencil.

''"I wish I had known all this before," said Pippin. "I had no notion of what I was doing."''

''"Oh yes, you had," said Gandalf. "You knew you were behaving wrongly and foolishly; and you told yourself so, though you did not listen. I did not tell you all this before, because it is only by musing on all that has happened that I have at last understood, even as we ride together. But if I had spoken sooner, it would not have lessened your desire, or made it easier to resist. On the contrary! No, the burned hand teaches best . After that advice about fire goes to the heart."''

''"It does," said Pippin. "If all the seven stones were laid out before me now, I should shut my eyes and put my hands in my pockets."''
 * ~ J. R. R. Tolkien, The Lord of the Rings, Book III, Chapter 11: The Palantír

A little while later, Sanya gives Dresden the sword Amoracchius in trust. Harry grumbles about having to be guardian of yet another one of the Swords of the Cross. The copy of The Two Towers fell open to the inside cover. There were word written in flowing in handwriting: "The reward for work well done is more work."