Lyman Frank Baum 
Emerald City Of Oz 

The Emerald City of Oz was originally published on July 20th, 1910 and is the sixth book in the Oz series written by L Frank Baum. It is the story of Dorothy Gale and her Uncle Henry and Aunt Em taking a tour of the Land Of Oz as they come to live in Oz permanently. Whilst they are touring the Quadling Country, the Nome King is assembling allies for an invasion of Oz. As he now has banished both his General and his Colonel he has to rely on advice from the old soldier Guph who is on the search for further recruits to take on the magicians of Oz.