It provides a popular presentation of set theory and four dimensional geometry as well as some mystical implications.

A foreword is provided by Martin Gardner and the 200+ illustrations are by David Povilaitis.

Several analogies are made to Flatland; in particular, 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.

Kirkus Reviews called it "animated, often amusing", and a "rare treat", but noted that the book eventually leaves mathematical topics behind to focus instead on "mysticism of the all-is-one-one-is-all thinking of an Ouspensky.

"[1] The Quarterly Review of Biology declared it to be "nice", and "at times (...) enchanting", comparing it to The Tao of Physics.