In Back to the Future it seemed so simple – get into the car, traverse the ages as you will and look pretty cool while doing it. But will time travel ever be possible? In The New Time Travelers, technical writer David Toomey puts forward a positive, though cautious, case.

In this, his third book, Toomey takes the reader on a tour of the current possibilities as they've evolved, and so pieces together an engaging sketch of 20th century physics.

Relativity and quantum mechanics are necessary ingredients of the mix, and a reader who can claim some knowledge of Einstein's Popular Exposition will be covering familiar territory – albeit with a different array of images to help explain some of the curlier concepts.

So too with quantum mechanics, which proves essential to any discussion of time travel into the past. If you've dabbled before, you'll be familiar with the double-slit experiment (see Cosmos 15, "Confronting the quantum enigma", p72) and perhaps more comfortable with some of the apparently strange concepts covered.

Yet, if travelling into the future is problematic, travelling into the past is more so. Still, says Toomey, there is a glimmer of light, particularly if humanity is prepared to put in the work needed to understand wormholes. The New Time Travelers is an exciting read, and if it's not quite a recipe book on how to create your own time machine, it certainly makes the subject much easier for the lay reader to grasp.

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