Out of Oz: The final volume in the Wicked years

Summary:

Glinda, former Throne Minister, held under house arrest by General Cherrystone, obtains the infamous Grimmerie, supposedly a volume of magical lore, coveted by Oz. Meanwhile, Liir's daughter Rain begins her quest to discover her true identity and unravel the layers of political and personal secrets that have caused strife and division in Oz.

Out of Oz is the fourth book in Gregory Maguire's series that reimagines the world of L. Frank Baum's Oz, starting with Wicked (which also inspired a Broadway show!) and continuing with Son of a Witch and A Lion Among Men.