The revolution is here. In breakthrough after breakthrough, pioneering physicists are unlocking a new quantum universe which provides a better representation of reality than our everyday experiences and common sense ever could. The birth of quantum computers - which, like Schroedinger's famous dead-and-alive cat, rely on entities like electrons existing in a mixture of states - is starting to turn the computing world on its head. In his fascinating study of this cutting-edge technology (first published as Computing with Quantum Cats and now featuring a new foreword), John Gribbin updates his previous views on the nature of quantum reality, arguing for a universe of many parallel worlds where 'everything is real'. Looking back to Alan Turing's work on the Enigma machine and the first electronic computer, Gribbin explains how quantum theory developed to make quantum computers work in practice as well as in principle. He takes us beyond the arena of theoretical physics to explore their practical applications - from machines which learn through 'intuition' and trial and error to unhackable laptops and smartphones. And he investigates the potential for this extraordinary science to allow communication faster than light and even teleportation, as we step into a world of infinite possibility.

What happens when the country's greatest logician meets the century's greatest physicist? In the case of Kurt Godel and Albert Einstein the result in Godel's revolutioinary new model of the cosmos. In the 'Godel Universe' the philosophical fantasy of time travel becomes a scientific reality. For Godel, however, the reality of time travel signals the unreality of time. If Godel is right, the real meaning of the Einstein revolution had remained, for half a century, a secret. Now, half-century after Godel met Einstein, the real meaning of time travel in the Godel universe can be revealed.

Why do we measure time in the way that we do? Why is a week seven days long? At what point did minutes and seconds come into being? Why are some calendars lunar and some solar? The organisation of time into hours, days, months and years seems immutable and universal, but is actually far more artificial than most people realise. The French Revolution resulted in a restructuring of the French calendar, and the Soviet Union experimented with five and then six-day weeks. Leofranc Holford-Strevens explores these questions using a range of fascinating examples from Ancient Rome and Julius Caesar's imposition of the Leap Year, to the 1920s' project for a fixed Easter. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.