If all you know of Oz comes from the movie musical, you owe it to yourself to read the book that inspired Hollywood. You will learn a lot more about Dorothy and her friends than the movie reveals. This first volume in what was to become a collection of 40 officially recognized books is not even the best in the series, but start your jouney here.
If you have read and enjoyed The Woman in White and The Moonstone, be sure to give this one a try. It contains a truly memorable "heroine" as well as a number of fascinating other characters. Collins does a good job of maintaining suspense and tension in this complex tale of tragedy and revenge. He also knows when to insert a strong dose of comic relief. Recommended.