In Glinda of Oz, princesses Dorothy and Ozma travel to stop a war in a remote region of Oz near the edge of Gillikin Country. There is an ongoing war amongst two rival tribes, the Skeezers and the Flatheads. Ozma decides to visit the region and try to mitigate the quarrel. They first travel to meet the Flatheads, who live on top of a mountain and are ruled by a Supreme Dictator. Being unable to talk him out of going to war, Dorothy and Ozma travel to an island city encased in glass, where they meet the leaders of the Skeezers, a vain narcissist who is determined to fight the war as well. Dorothy and Ozma are imprisoned, and then trapped when the Queen of the Skeezers sinks the island and then is turned to a swan by the Flatheads, leaving it up to Glinda the Good sorceress and Dorothy's other friends to rescue them.
Being Baum's last Oz book, Glinda of Oz is a bit different from its predecessors. It depicts a slightly more technologically advanced Oz and has some darker themes than in previous books.
Glinda of Oz provides examples of:
- Affectionate Nickname: Ozma repeatedly refers to Dorothy as "Dorothy Dear".
- And I Must Scream: People don't age or die in Oz. Yet, a paragraph in Glinda Of Oz goes into depth on what horrible things enemies could do to Dorothy if they so wish. She could be cut into pieces and scattered about, though she wouldn't feel any pain. She could also be buried alive.
- Baleful Polymorph:
- The war began over a dispute involving fishing. The Skeezers transformed the Flatheads' Supreme Dictator's wife into a golden pig.
- Queen Coo-ee-oh learned her magic from the three Adepts, but betrayed them by turning them into fishes.
- The Su-Dic turns Coo-ee-oh into a swan. She never gets turned back. Turns out she's happier as a swan though.
- Darker and Edgier:The book features some morbid elements, such as talking skeletons as well as evil magic involving pickled critters and books written with blood. Many attribute it to L. Frank Baum being close to death.
- Does This Remind You of Anything?: It's often analyzed as a Coming-of-Age Story. The talking animals and living objects of previous books are put aside, with Dorothy and Ozma instead going off into the dangerous world on their own. They find that they can't solve the issue by themselves, so they ask an older woman for help.
- Domed Hometown: The island of the Skeezers is covered by a glass dome, and can be submerged in or raised above the surface of the lake with a spell known only to the queen.
- Never Say "Die": It is mentioned that Dorothy could be "destroyed" by evil magicians if she wasn't magically protected well enough. This is noted after a paragraph on various horrible Fates Worse Than Death that can occur to her.
- The Power of Blood: Queen Coo-ee-oh has a shelf of books written in blood.
- Royals Who Actually Do Something: The story starts with Princesses (in name alone) Ozma and Dorothy arriving at Glinda's to talk. Ozma and Glinda discuss how they could improve the lives of their citizens even more, though Dorothy has no interest in such politics. Instead, she goes to the Great Book and learns about the impending war, triggering the plot.
- Secondary Character Title: Glinda is at least present from the beginning of the book, but the true main protagonists are Dorothy and Ozma.
- Silly Reason for War: At first it seems the Flatheads and Skeezers are going to war over the right to fish in the Skeezer's lake. However, it is revealed later that there is a deeper reason that makes the war not as silly as it seems on the surface.
- Underwater City:The Skeezer's city can become one temporarily, but no one can enter or leave the city once submerged.
- What's Up, King Dude?: Dorothy is a very friendly princess that makes most of everyone in Oz feel like she's their personal friend.