How humanity came to contemplate its possible extinction.From forecasts of disastrous climate change to prophecies of evil AI superintelligences and the impending perils of genome editing our species is increasingly concerned with the prospects of its own extinction. With humanitys future on this planet seeming more insecure by the day in the twentyfirst century existential risk has become the object of a growing field of serious scientific inquiry. But as Thomas Moynihan shows in XRisk this p