A tide of racism, nationalism, and authoritarianism is sweeping the world: from Donald Trump in the United States to Marine Le Pen in France, from Nigel Farage in Britain to Norbert Hofer in Austria. With the world economy hobbled by debt and stagnation, society being torn apart by austerity and inequality, and a political system paralysed by corporate power, support for the Far Right is surging. This book is an urgent call to arms. It seeks to rally the Left around a vital historic task: the immediate building of an international mass movement to stop the rise of fascism.