Statistics rule our world. Every day, most of us will read or watch something in the news that is based on a statistic in some way. Sometimes it'll be obvious - 'X people develop cancer every year' - and sometimes less obvious - 'red wine protects against cancer'. But still, it happens all the time. The trouble is, statistics, when used carelessly, are dangerous, and can bring forth demons. They are an immensely powerful tool for understanding the world; the best tool we have. But in the hands of unscrupulous, careless, or simply clueless people, they can easily be used to tell stories that are misleading or even flat-out false. This book is a guide to how and when to trust them - and perhaps more importantly, when not to.