Flatland: A Romance of Many Dimensions is a satirical novel. Written pseudonymously by "A Square", the book used the fictional two-dimensional world of Flatland to comment on the hierarchy of Victorian culture, but the novella's more enduring contribution is its examination of dimensions.

Although it did not achieve popular success on its publication in 1884, Flatland gained a broad audience after the publication of Albert Einstein's general theory of relativity, which focused attention on the concept of a fourth dimension.

The book enjoyed another renaissance with the advent of modern science fiction in the late 1930s and is now widely acknowledged as a pioneering work of mathematical fiction.