The Fourth Dimension is a non-fiction work written by Rudy Rucker, the Silicon Valley professor of mathematics and computer science, and was published in 1984 by Houghton Mifflin. The book is subtitled as a guided tour of the higher universes. The foreword included is by Martin Gardner, and the 200+ illusrations are by David Povilaitis. Like other books by Rucker, The Fourth Dimension is dedicated to Edwin Abbott Abbott, author of the novella Flatland.
The Fourth Dimension guides you on a mind-expanding journey; the book is designed to alter the reader's perceptions of the universe through the exploration of a fourth dimension (a fourth physical dimension, rather than the simpler notion of time as a fourth dimension). The information gives the reader a much better understanding of the concept of higher dimensions, whose existence must be presumed in order to complete some of the mathematical equations of quantum mechanics. Abbott's Flatland is put to use by means of analogies, which are used throughout the book. Rucker compares how a square in Flatland would react to a cube in Spaceland to how a cube in Spaceland would react to a hypercube from the fourth dimension.
In addition to the 200 pages of the guided tour of the higher universes, many puzzles (see mental-skill game) are included to help the reader gain the mental tools necessary to envisioning a fourth dimension.