What causes climate change, social breakdown, rampant inequality and the creeping spread of ubiquitous surveillance? Capitalism. What is the only alternative to capitalism? Socialism. Socialism cannot, however, remain static if it is going to save civilisation from these catastrophes. In this urgent manifesto for a 21st century left, Jeremy Gilbert shows that we need a revitalised socialist politics that learns from the past to adapt to contemporary challenges. He argues that socialism must overcome its industrial origins and give priority to an environmental agenda. In an age of global networks, digital technology and instant communication, central government diktat and restrictions on free speech and movement must be jettisoned. We need to control the economy rather than let it control us - but we must do this by empowering workers, citizens and communities to run their world their way. It's time to take back the wealth, the services and the platforms that our own energy has built. In the digital age, it's time for a new socialism.