A short guide to the six theories that try to explain the wild world of the quantum. Quantum physics is strange. It tells us that a particle can be in two places at once. Indeed, that particle is also a wave, and everything in the quantum world can be described entirely in terms of waves, or entirely in terms of particles, whichever you prefer. All of this was clear by the end of the 1920s. But to the great distress of many physicists, let alone ordinary mortals, nobody has ever been able to come up with a common sense explanation of what is going on. Physicists have sought 'quanta of solace' in a variety of more or less convincing interpretations. Popular science master John Gribbin takes us on a delightfully mind-bending tour through the 'big six', from the Copenhagen interpretation via the pilot wave and many worlds approaches. All of them are crazy, and some are more crazy than others, but in this world crazy does not necessarily mean wrong, and being more crazy does not necessarily mean more wrong. AUTHOR: John Gribbin's numerous bestselling books include In Search of Schrodinger's Cat, The Universe: A Biography, and 13.8: The Quest to Find the True Age of the Universe and the Theory of Everything. He is a Visiting Fellow at the University of Sussex, and was described as 'one of the finest and most prolific writers of popular science around' by the Spectator.