"Now, the people!" These words are an invitation to action. They allude to the hope of a response to the ruination of the beauty the world and the deadly intensification of the ecological crisis. They refer to the desire to turn a page in the history of human civilisation after the disasters created by the reign of finance. They call for permanent insubordination against an unjust and destructive world order. Jean-Luc Melenchon defended these principles as the candidate of La France insoumise in France's 2022 presidential elections, where he came within a whisker of breaking through into the second round against Emmanuel Macron, representative of the bourgeois political bloc. Action is blind without theory. Theory is vain without action. Politician and theorist Melenchon proposes here an ambitious analytical framework for sorting out and interpreting the facts that face us at this turning point in the history of the world. He has worked on this major work over the last fifteen years, at a time when citizens' revolutions were erupting in the four corners of the world, from the Maghreb to New York, from Chile to Lebanon, via the French yellow vest protests. Melenchon proposes here a theory of the era of the people and the citizens' revolution as a strategic orientation and a way of grasping the world today. Its aim is to help us to think in order to act and go on to change the world.