I think we're garaunteed to have a sequel. Anyone else remember that grandmother who was willing to trade her grandson, Tip, for the broom? In the original OZ books, Ozma (princess of Oz, she's mentioned a little bit in Maguire's books) was disguised as a boy named Tip. And why else would this insignificant little scene show up in Liir's flashback? I'm betting that in the next book, we'll see the restoration of the Ozma rulership.