The climate crisis threatens global social collapse. Within a generation. What to do? Common Sense for the 21st Century outlines how movements around the world now need to come together to start doing 'what works'. This means engaging in mass civil disobedience to make real change happen. This booklet is not just theory, it is the call to action. The political class is not going to save us from extinction. We will be saved by ordinary people breaking the law. This is common sense - only Rebellion can save us now. Roger Hallam is the co-founder of Extinction Rebellion. He was an organic farmer in Wales, turned prize-winning academic, who applied his social scientific research to developing the radical tactics and strategy for this new climate change movement. His message to everyone is: 'Think on it but then act. Join the Rebellion. Let's get to it.'