In the 2017 general election, Jeremy Corbyn pulled off an historic upset, attracting the biggest increase in the Labour vote since 1945. For the first time in decades, socialism is back on the agenda—and for the first time in Labour’s history, it defines the leadership. Richard Seymour tells the story of how Corbyn’s rise was made possible by the long decline of Labour and by a deep crisis in British democracy. He shows how Corbyn began the task of rebuilding Labour as a grassroots party, with a coalition of trade unionists, young and precarious workers, students and ‘Old Labour’ pugilists, who then became the biggest campaigning army in British politics. Utilizing social media, activists turned the media’s Project Fear on its head and broke the ideological monopoly of the tabloids. After the election, with all the artillery still ranged against Corbyn, and with all the weaknesses of the Left’s revival, Seymour asks what Corbyn can do with his newfound success.