Sphereland: A Fantasy about Curved Spaces and an Expanding Universe, by Dionys Burger, forward by Isaac Asimov

The Great Books and World Classics Discussion Group is a joint project of Northern New Jersey Mensa and Mensa in Atlanta.  Sphereland was inspired by Flatland, which was a story about a two-dimensional world in which the narrator (a square) imagines a linear world and a three-dimensional world. Sphereland deals with higher dimensions.

Read the book: Sphereland : a fantasy about curved spaces and an expanding universe : Burger, Dionys : Free Download, Borrow, and Streaming : Internet Archive

There is also a movie. See the ‘Flatland 2: Sphereland’ Official Trailer