Paradox in Oz is a 2000 novel by Edward Einhorn, which serves as a continuation of L. Frank Baum's original Land of Oz series as well as a Milestone Celebration of the 100th anniversary of The Wonderful Wizard of Oz.
Panic strikes Oz as Omby Amby discovers gray hairs in his green beard, and other Oz residents realize they are aging or hitting puberty. Princess Ozma consults Glinda the Witch of the South, and they conclude the anti-aging spell which has kept anyone in Oz from aging since Ozma took the throne has been broken. They find that the spell was cast on The Man Who Lives Backwards, now a baby, to keep him from growing any younger and disappearing from existence. Thus, the only way for Ozma to reinstate the spell is to meet The Man Who Lives Backwards as an adult through time travel, with the help of Tempus the Parrot-Ox. Along the way Ozma accidentally changes the timeline and creates a dystopic version of Oz, and has to do more time traveling to put things right again.
- The Ageless: What the people of Oz are accustomed to being, at least for the past century or so.
- Alternate Self: Ozma runs into dozens of past selves when she unsuccessfully tries to stop herself from changing history and goes back in time a little further every time she fails.
- Armed with Canon: We get a sly Take That! aimed at Ruth Plumly Thompson's renaming of Omby Amby in her Oz books; in the alternate Obsidian City version of Oz, Omby Amby is named Wantowin Battles, which Ozma immediately declares is a horrible name. This also indirectly insinuates that Thompson's books take place in an alternate Oz from Baum's, at least according to this book (which, not being published by the original publishers Reilly & Lee, can't be considered official canon itself).
- Bad Future: The bad future of Oz includes the Obsidian City, ruled over by an evil Wizard of Oz.
- Bizarrchitecture: Absurd City is composed entirely of this, looking like something out of an Escher painting.
- Butterfly Effect: Ozma stops the King of Oz from drinking from the Fountain of Oblivion, which in her timeline caused the wicked king's memory to be erased and turned Oz into a utopia; instead he remains cruel, and Oz becomes a dystopia.
- Dystopian Oz: Ozma accidentally creates a Bad Future for Oz after changing the past while time traveling. This dark version of Oz has the Obsidian City as its capital, ruled over by an evil dictator version of the Wizard, with a bloodthirsty version of Nick Chopper (who becomes the Tin Woodman in the normal timeline) as his right hand man.
- First Gray Hair: Omby Amby's first gray hair causes him to panic, and cover his face with a fan when he goes to see Ozma.
- Have We Met Yet?: Tempus the Parrot-Ox knows Ozma as soon as she first meets him; at the end of the book, he meets Ozma for the first time even though Ozma has gotten to know him.
- Meet Your Early Installment Weirdness: Ozma gets to meet herself when she was Tip at one point, having a brief conversation and planting the seeds of him deciding to run away from Mombi.
- Mind Screw: Absurd City, a town in the northern Gillikin Country of Oz full of optical illusions and Penrose stairs.
- Mix-and-Match Critters: The Parrot-Ox, which of course, is a parrot crossed with an ox.
- The Multiverse: When reality begins to crack around her Ozma sees into other versions of Oz in other universes, including what is apparently an Animated Adaptation, one of the old silent movies, and a stage adaptation. The accompanying illustration shows more detail, as we see dozens of different adaptations through the cracks.
- Original Flavor: The book is really trying to go for the original feel of the Oz books, from not only the writing style but the illustrations, and even using the same Schoolbook font the ones published by Reilly & Lee used.
- Plot Hole: Pointing these out is actually how to make a parrot-ox appear; Ozma first summons Tempus by wondering how she knew what a horse was when she gave life to the Sawhorse in The Marvelous Land of Oz when it is stated in Dorothy and the Wizard in Oz that there are no horses in Oz.
- Punny Name: The parrot-ox. You don't need to think too hard about it.
- Royals Who Actually Do Something: Ozma has always rarely been able to participate in adventures; only in a couple of Baum's books was she a main character. But in this book it's up to her to save Oz.
- Stable Time Loop: In this book, Ozma herself inspired Tip to run away from Mombi, paving the way for him to be transformed back into Ozma because his future self convinced him to.
- Time Stands Still: The only way for Ozma to communicate with The Man Who Lives Backwards is to stop time.