The Assassin's Creed games mostly have a present-day component, where the protagonist's descendent enters the Animus, reliving the protagonist's life. Since this is merely replaying memories, we don't actually affect the past in the game, but, in Assassin's Creed II: Revelations:
With the power of the Piece of Eden, Ezio the ancestor communicates with Desmond the descendent.
However, from the AC novels I have read (the first five to be published, IIRC), there is no mention at all of present day events. I don't recall how exactly the event in the spoiler block happened in the corresponding book, but Desmond Miles makes no appearance, of that I am sure.
Why aren't the present day events and characters part of the AC books?