The Star Wars: The Rise of Skywalker novelization further fleshes out how Emperor Palpatine survived Return of the Jedi. When the first Rise of Skywalker trailer debuted at last year's Star Wars Celebration, fans were very surprised to hear the classic villain's signature laugh, confirming his return. Palpatine had seemingly been killed at the end of Return of the Jedi, and the previous two sequel trilogy installments did little (if anything) to hint Darth Sidious was still lurking in the shadows, pulling the strings. Viewers spent months theorizing how Palpatine would be brought back.
When The Rise of Skywalker premiered last December, some viewers were disappointed the film didn't spend too much time addressing that topic, simply paying lip service to director J.J. Abrams' favorite scene in the prequels (repeating Palpatine's famous line about the dark side and unnatural abilities). It's one of the reasons why Rise of Skywalker critics felt Palpatine's role felt sudden and rushed. For those let down by how the movie approached the Emperor's survival, the official Rise of Skywalker novelization provides greater detail to answer some lingering questions.
Towards the end of the book, during the scene where Rey feigns partaking in the Sith Ritual, author Rae Carson writes a passage where Rey has visions of Palpatine's past, beginning with him being thrown down the Death Star shaft. It's here where it's explained exactly how Palpatine survived:
"Plagueis had not acted fast enough in his own moment of death. But Sidious, sensing the flickering light in his apprentice, had been ready for years. So the falling, dying Emperor called on all the dark power of the Force to thrust his consciousness far, far away, to a secret place he had been preparing. His body was dead, an empty vessel, long before it found the bottom of the shaft, and his mind jolted to a new awareness in a new body - a painful one, a temporary one."
This definitely clears a lot up, resolving some key issues people had with Palpatine returning in the first place. While many were intrigued by the tease in the initial Rise of Skywalker trailer, fans couldn't help but point out that Palpatine had fallen down a shaft and then the Death Star blew up. It was confusing for some that Palpatine was still alive (albeit in a physically deformed state) and responsible for the events of the sequel trilogy. The Rise of Skywalker novelization confirms Palpatine's essence had left his original body prior to the Rebel Alliance's victory at Endor as part of his contingency plan. The Emperor was always scheming, looking to stay ahead of his adversaries, so this makes sense. It also makes Return of the Jedi's ending all the more tragic; the Rebels partied on Endor like they had won, but Palpatine was still out there all along.
Whether The Rise of Skywalker would have benefitted from including this information in the movie is open for debate. Some viewers certainly would have appreciated a more detailed exploration concerning Palpatine (and there was some Palpatine backstory cut), but a case can be made what's presented in the film gets the job done. The prequel callback lets people know Sidious channeled his immense dark side power and cracked Plagueis' secret to immortality. Exact specifics would have been nice to know, though arguably aren't needed for The Rise of Skywalker's story. It can be inferred in the movie.
Star Wars: The Rise of Skywalker is available on Digital and hits Blu-ray March 31, 2020.
Source: Star Wars: The Rise of Skywalker Novelization