Lights Out: How It All Ends by the editors of Scientific American

Traditionally, the four horsemen of the apocalypse are war, famine, plague and death; but while classical authors were familiar with only four horsemen, modern ones could add events such as environmental devastation and nearby supernovas. In this eBook we look at several "end of the world" scenarios – or at least, things that could make human life really difficult. Each section discusses a different horseman, from plague, famine and war to cosmic events, extreme weather and environmental collapse. Some are apocalyptic, others less so, but they show that even if one doesn't take the Book of Revelation or the supposed Mayan prophecy as a template, thinking about our own end is fascinating – and sobering. Some endings only affect humans – mass starvation for us isn't likely to bother rats – whereas others eliminate all life on Earth. The good news is that the ability to map out the end also grants us the power to avert it, at least in some cases. Included in this book is a seminal piece outlining the possibility of "nuclear winter." Former Soviet leader Mikhail Gorbachev has stated that such studies were a major impetus for him to seek to reduce tensions with the United States. As a species we've tackled ozone depletion, and there's no reason other environmental problems can't be dealt with as well. The question was never technical ability, only political will. So while much of this book might seem a gloomy exercise, there's an optimistic side too: we may not endure eternally, but stupidity or hubris doesn't have to end our world prematurely.