The climate crisis threatens global social collapse within a generation. 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. 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. His message to everyone is: 'Think on it but then act. Join the Rebellion. Let's get to it.'