This is a book about universes. It tells a story that revolves around a single extraordinary fact: that Albert Einstein's famous theory of relativity describes a series of entire universes. Not many solutions to Einstein's tantalising universe equations have ever been found, but those that have are all remarkable. Some describe universes that expand in size, while others contract. Some rotate like a top, while others are chaotically unpredictable. Some are perfectly smooth, while others are lumpy. Some permit time travel into the past. Only a few allow life to evolve within them; the rest, if they exist, remain unknown and unknowable to conscious minds.

Our story will encounter universes where the laws of physics can change from time to time and from one region to another, universes that have extra hidden dimensions of space and time, universes that are eternal, universes that live inside black holes, universes that end without warning, colliding universes, inflationary universes, and universes that come into being from something else - or from nothing at all.

Gradually, we are introduced to the latest and the best descriptions of the Universe as we understand it today, together with the concept of the 'Multiverse' - the universe of all possible universes - that modern theories of physics lead us to contemplate. Here, in The Book of Universes, we are confronted with the most fantastic and far-reaching speculations within the entire realm of science.