Why can't we tickle ourselves? Which properties give you the best chance of winning Monopoly? What would happen if you fell into a black hole? Is it possible to hurt your brain if you think too much? In this entertaining and enlightening tour of day-to-day life, award-winning writer and scientist Robert Matthews tackles everything from the puzzling maths of odd socks to the real 'string theory' mystery: how does string acquire all those unwanted knots?