Sci-Fi; Stephen Colbert called it “Heinlin’s Universe” - Humanity lives on a space ship, Civilization crumbles and is rebuilt, they don’t know they’re on a ship, gravity is lessened as you get to the middle of the ship. Spoiler.

[Mason]

Spoilers ahead

Stephen Colbert talked about this book when he was interviewed on a podcast with Merry and Pippin actors from Lord of the Rings. Colbert called it “Heinlin’s Universe.” Google couldn’t help me because I’m probably spelling that name wrong.

Colbert said the book was a sci fi classic, where humanity lives on a space ship, but society crumbles and some humans move to parts of the spinning ship that are closer to the center, but no one knows that they’re entire world is actually a space ship— they just think it’s the world and how it always has been. Because the ship is spinning, gravity is weaker towards the center of the ship. As time goes on, generations are born with defects because of lack of gravity. The children that have mutated are called “Muties.” The main character(s) fight off the mutants and travel to the places where gravity is weaker when they eventually (SPOILER I THINK) find the center of the ship— the captains room— and discover that they are on a space ship and had no idea.

[Emily]

I think you are looking for Orphans of the Sky by Robert A. Heinlein

Universe is one of the books that is part of this book.
https://en.wikipedia.org/wiki/Orphans...

[Christine]

Agered.. sounds like Orphans of the Sky