Flatland:

How would a creature limited to two dimensions be able to grasp the possibility of a third? Edwin A. Abbott’s droll and delightful “romance of many dimensions” explores this conundrum in the experiences of his protagonist, A Square, whose linear world is invaded by an emissary Sphere bringing the gospel of the third dimension. Part geometry lesson, part social satire, this classic work of science fiction brilliantly succeeds in enlarging all readers’ imaginations beyond the limits of their “respective dimensional prejudices.” Unless you’re a mathematician, the chances of you reading any novels about geometry are probably slender. But if you read only one in your life, this should be at the top of your list. Flatland imagines a two-dimensional world inhabited by sentient geometric shapes who think their planar world is all there is. But one Flatlander, a Square, discovers the existence of a third dimension and the limits of his world’s assumptions about reality and comes to understand the confusing problem of higher dimensions. The book is also quite a funny satire on society and class distinctions of Victorian England.