A long time ago in a galaxy far away, the chances are that nothing happened and if it did we are never likely to know. This book goes through every fallacious belief we have ever held about the possibilities of faster-than-light travel, transporter beams, wormholes, flying saucers and close encounters. It systematically builds them up and takes them apart.

To demonstrate how aliens are most likely not among us or at least not in the manner we may expect, Rod MacDonald has created the Exordicans. They, he tells us, lived on a distant planet and many millennia before Earth came to be inhabited. The planet civilisation developed to such an extent that interstellar space travel became possible.

Alongside the ability to choose more or less eternal life, this means that these 'people' can travel. They become the explorers of space but the circumstances allowing them this chance means they are the most introspective bunch ever to set off on a journey. The Exordicans travel in several converted asteroids and eventually end up here.

He details the changes their bodies and minds go through and reasons they might have for stopping off on Earth. Soon it becomes apparent that he is describing the familiar picture that is drawn by abductees around the world: the grey alien. He develops his arguments quite comprehensively in a series of chapters.

It is a learned and scientific approach that manages not to talk down to readers like me. It is an essay that chooses fact over belief but backs up his arguments in an enjoyable and entertaining way.

It is not a trivial approach and may well give SF directors cause to throw away their film scripts as he debunks practically anything ever made or wrote about the subject with suitable references to popular culture.

With two useful appendices about evolution and extending life you will now be armed with the knowledge to shoot down in flames anyone who dares to suggest that the alien encounters of 'Taken' are in any way realistic scenarios.

Despite all that it makes me wistful because with this knowledge backed up with solid science, I will no longer 'watch the skies' for ET or hope for a close but benign encounter. Read and enjoy but ‘Star Trek’ will never be the same again!

Sue Davies