Flatland: A Romance of Many Dimensions, though written in 1884, is still considered useful in thinking about multiple dimensions. It is also seen as a satirical depiction of Victorian society and its hierarchies.
A square, who is a resident of the two-dimensional Flatland, dreams of the one-dimensional Lineland. He attempts to convince the monarch of Lineland of the possibility of another dimension, but the monarch cannot see outside the line. The square is then visited himself by a Sphere from three-dimensional Spaceland, who must show the square Spaceland before he can conceive it. As more dimensions enter the scene, the story's discussion of fixed thought and the kind of inhuman action which accompanies it intensifies.