The mood of the book shifts over the course of the story, from exciting to bittersweet. In the first chapter, Dorothy finds herself on the ultimate adventure. She is swept into the air in fantastical fashion, and she wakes in a new land that is far more vivid and strange than the farm in Kansas. She must learn about the politics, people, and geography of this new place. She has a series of dangerous and suspenseful encounters that allow readers to live vicariously, even if they themselves live on a dusty farm in Kansas.
But the more challenges Dorothy overcomes, the more friendships she forges. By the end of the book, she has formed a tight-knit group with the Cowardly Lion, the Scarecrow, and the Tin Woodman. The book that began as a fun tale of a "normal" child in a wild and strange place turns into the story of difficult goodbyes. In Chapter 23, Dorothy captures the bittersweet mood when her friends tell her how much she has done for them:
‘This is all true,’ said Dorothy, ‘and I am glad I was of use to these good friends. But now that each of them has had what he most desired, and each is happy in having a kingdom to rule besides, I think I should like to go back to Kansas.’
Dorothy acknowledges both the importance of friendship and the importance of finding one's own place in the world. All of them have their own home; her friends belong in different parts of Oz, and she belongs in Kansas. Even though their parting is painful, Dorothy does not wish she had never gone on her journey and met her friends. The novel winds up suggesting that all of the connections we make come to an end, but that the fulfillment they bring is worth the sense of loss. The reader is left feeling similarly about the ending of the book. Baum invites readers to carry forward what they have learned into their everyday lives, even if these everyday lives are mundane.