This is the last Oz book written by L. Frank Baum. It is one of the best in the series, with Dorothy, Ozma, and Glinda in an adventure that takes them to an amazing crystal-domed city on an enchanted island. This island is situated in a lake in the Gillikin Country. Ozma and Glinda are confronted by powerful magic and determined enemies. For a time Dorothy and Ozma are prisoners in the crystal-domed city which is able to submerge below the surface of the lake. Few of the Oz books equal this one in suspense and mystery-a story that is truly "out of this world.