Tedious. 
 That is the first word that comes to mind while I was reading this. There is so much needless minutiae about old books that, frankly, I found boring. I'm not a professor of antique books, so knowing the weight of vellum or what symbology is attached to a tree is lost on me. 
 Aside from the excess details, there was also the problem of two years...two years between books, and little or no explanation of who the many varied characters were, or much of a review of what happened in the last books. If you are going to read the trilogy straight through, you won't have a problem, but I felt completely lost. 
 The constant jumping around in location also helped to confuse me. Once I got used to one setting they'd move again. Not to mention the changing POVs...first person, third person...it was a bit jarring.