I'm in love with the MGM film, The Wizard of Oz, as I have always been since I was three years old and was terrified of the Wicked Witch! After reading the novel though, I found many differences and information that was not provided in the movie...which is a good thing. There is a big significance between the two endings of the works, since it entails the "moral of the story" and serves to wrap it up.
One difference I thought is worth discussing is the Wicked Witch's death. In the movie this is the beginning of the end, the climactic moment. Contrastly, in the novel, it occurs on page 154 in a book consisting of 261 pages, so there is still about 100 pages to go after her death (clearly not the ending). As well, in the movie it was a huge scene where Dorothy and her friends are running for their lives and all the guards have them surrounded. The witch wants to start with the scarecrow and begins to set him on fire. As this happens, Dorothy reaches for a bucket of water (conveniently right behind her) and throws it upon the scarecrow to extinguish the fire. By chance, she hits the Wicked Witch as well and the witch dramatically deflates and gives her finals words while she wails and melts away. This scene is very different in the novel. The witch plans a trick to have Dorothy stumble on an invisible iron brick while simply walking in the hall. She successfully stole on of the silver slippers and denied giving it back to Dorothy. In Dorothy's anger, she dashed water at the witch on purpose, but not knowing it would anialate her, and the witch began to melt. Dorothy apologizes for her causing the witch death and the witch gives a detailed explanation of how she was in disbelief that Dorothy was the one to cause her demise. This scene is very anti-climactic with the apology, the extended conversation between Dorothy and the witch WHILE she's melting, and the reason behind the throwing of the water.
After the witch is killed in the movie, Dorothy and her friends immediatly appear before the Great Oz (but we know that time has passed by use of film techniques). He is revealed as a fraud, but still gives each character a placebo of their desire and offers to take Dorothy home with him on his hot air balloon. When she does not succeed in leaving with him, Glenda immediatley appears traveling in her pink bubble (like a bubble blown up from pink gum) and tells her how to get home. In the novel, all of this is lengthened completely and there are many more villains to pass before they reach Glenda such as the fighting trees, the spider in the forest, and the Hammer Heads. Throughout the film, the Wicked Witch of the West is identified as the main villian from beginning to end. She stalks them on their entire journey to Oz and once she is defeated, no more villains approach them. The book is different in that is does not identify one clear cut villian and I feel it was a good thing to cut it from the movie and have one complete antagonist.
Getting more specific, Dorothy uses a famous phrase in the film, "there's no place like home," while this is non-existent in the novel. In the works original form, the book, she requests, "take me home to Aunt Em!" This is a minor detail, but in the film it makes a huge impact upon audiences and the entire story. This gives the story a moral and wraps it up nicely for the viewers to understand exactly what the moral is. In the novel she phrases it differently which lacks the dramatic effect given by the film.
She also becomes very fond of the scarecrow compared to everyone else; he is her favorite and she expresses this in her farewell to them in the film. Though, in the book she shows empathy towards him equalivalent to the other three. She kissed the lion and the tinwood man, but hugged the scarecrow because his face is painted and in the end the narrator says, "she found she was crying herself at this sorrowful parting from her loving comrades." Contrastly, in the film she states that she will miss the scarecrow the most, singling him out while in the book she cries about all of them. I feel the movie creates a bond between the two to show not only friendship but best friends and like in most hollywood movies, a wing man/right hand man.
Lastly, a major change from the book to the movie is the dream plot provided by MGM's version. When Dorothy arrives clicks her heels she is, what I would call teleported (witht he cirlces and music), back to her bed where Auntie Em is trying to nurse her back to health with Uncle Henry. All the men who live in Kansas by the farm also appear, including the magician, and she tells them how she went to Oz and they were all there with her! Basically, it is concluded that it was a dream. Though, in the Baum's book, Dorothy appears back in Kansas standing in front of their newly built house. Aunt Em rushes out to her asking where she has been! This shows that she has not been present and asleep while in Oz. How long does it take to build a house? She must have been gone for a very long time as well. I believe MGM made it a dream to make the story more believable and to keep her in the house during the entire Oz adventure since it might be an eerie thought for young children watching if she really was gone for months. Also it shows that one doesn't have to go on a long adventure or runaway to learn that "there's no place like home." They can have a disturbing dream or thought of losing the ones they love and should be able to recognize where they belong.
All in all, I prefer the film version of this tale. Baum provided a great source, but MGM adapted it to be a classic.