How The Wizard Came To Oz, with this second book that also has ties to Land Of Oz and the original 1902 WOZ musical. How The Wizard Saved Oz carries on during the time after Oscar Diggs became established as "the Great and Powerful Oz", but before Dorothy shows up.
In the story, the Wizard takes off with the Queen of the Field Mice to find out what happened to her subjects that have gone missing. They go through the underground passage underneath the Emerald City which was originally the throne room of the former King Pastoria's, and then head through the lands of the Whozis and the Whatzis. The Wizard then happens across the strange pumpkin-shaped house of the witch Mombi, where he makes a hasty retreat after realizing her wicked intents. They finally make it to the city of Lanvendoria, and encounter a rather sizable Wogglebug. However, the Wizard becomes concerned when he spies the evil General Riskitt, who is the evil brother of Pastoria, and rival to the throne of Oz. Riskitt goes to see Mombi who has created a special machine powered by the field mice to give him all the magic in Oz. Mombi betrays him, and uses the machine for herself, but it backfires when the Wizard uses some growth powder to temporarily turn all the field mice larger. The magic returns, and Mombi flees to her cottage in the north(where she is keeping Tip). The mice go back to normal size, and the Mouse Queen helps the Wizard in a final battle with General Riskitt who falls down a crack in the Earth.
I thought this was a little more lighthearted story from the previous chapter Abbott did, although How The Wizard Came To Oz told a slighty better story. The main difference is that the first one skimmed alot through the Wizard's ascension in Oz, while as this one was more of a complete stand-alone story of the Wizard's early days. The book continues some great illustrations by Abbott done in the style of W.W. Denslow. General Riskitt is not shown in the regular Oz books, but was an original character from the first stage play created by Baum himself, although the idea of Riskitt being Pastoria's brother was done exclusively for this book. Check out this and other great Oz books at Books Of Wonder, along with more of Abbott's works.