The Glinda Letters is an epistolary novel composed of letters written by Glinda and sent to the Wizard, Oscar Diggs, while he is in a self-imposed exile in Emerald City. Glinda writes a letter to the Wizard each year on her birthday, and also when events in Oz deem it necessary. Each letter details significant information that Glinda is learning and that she believes is important for the Wizard to know. Through these letters, Glinda reveals her true soul to Oscar, bathed in tears, scorched in anger, and tempered with the fine fury of decades of wisdom. She grows from the angry child into the fearless sorceress sworn to protect Oz from all enemies.

Introduction to the Hidden History of Oz.