Trivia: Here are some interesting tidbits about where some of the aspects of the movie came from, which is a compilation of the books following the first. Jack Pumpkinhead, the Powder of Life, the Gump, Mombi, Ozma (Tip) and the escape off the top of the roof all come from 'The Marvelous Land of Oz'. The multiple heads angle, the Gnome King's Nick-Nack game, the chicken coop, Billina, and Tik-Tok all come from 'Ozma of Oz'. The tunnel under the Deadly Desert that Mombi uses to get to the Gnome King seems to come from 'The Emerald City Of Oz'.
Trivia: Since the ruby slippers were created for the 1939 Wizard of Oz movie (the book used silver shoes instead), they are still protected by copyright. Disney had to pay MGM a huge sum of money for the rights to use them in Return to Oz, where they take the place of the magic belt in the books.
Trivia: The only film directed by Oscar-winning film and sound editor Walter Murch. During principal photography, some production troubles almost caused the film to be shut down. Murch's friend George Lucas (of "Star Wars" fame) evidently watched some of the footage Murch had already shot, and impressed by what he saw, convinced Disney to resume production.