Ozma of Oz by L. Frank Baum
Ozma of Oz was first published on July 29, 1907, and was the third book of L. Frank Baum's Oz series. Happily, Dorothy returns in this book, after being absent from The Marvelous Land of Oz.
Uncle Henry has been ordered by his doctor to take a vacation from his Kansas farm and he goes to Australia. He and Dorothy are aboard a steamship traveling there when they are caught in a fierce storm and separated. Dorothy is blown overboard along with a yellow hen - Billina - from her uncle's farm that was on the ship. The movie Return to Oz also gets many of its ideas from this book, especially the lunch pail tree, which I find fascinating.
Dorothy and Billina are constant companions during this tale. We also get to meet Tic-Toc, the Nome King, and the hungry Tiger. Dorothy is also reunited with the Scarecrow, the Tin Woodman and the Lion.