Are there parallel universes? The idea that there might be many worlds and parallel universes - universes in which, rather than reading this, you are still asleep; in which you are happier, unhappier, richer, poorer, or perhaps even dead - is one which has crossed over from academic physics debate into a staple of science fiction. But what is the basis for the suggestion? Plus, our free online mathematics magazine, investigates the physics behind the controversial concept.

Read the articles in the Plus 'Science Fiction, Science Fact: Are There Parallel Universes' package.