"In his Autobiography, John Stuart Mill described himself as "under the general designation of Socialist". Yet Mill remains most famous as the author of On Liberty, that classic defence of free speech, free trade, and freedom. In this--the first book-length treatment of Mill's self-designation--Helen McCabe offers a radical re-reading of Mill, introducing a new figure in the canon of political thought: Mill the socialist. McCabe charts Mill's interactions with socialism, from his early debates against Owenites through his befriending by Saint-Simonians to his excitement over the revolutionary events of 1848, exploring how his changing relationship to the radicalism of his youth led Mill to socialism. She explains how Mill's adoption of socialist ideas about history and progress led him to advocate many liberal reforms 'for now', but that this does not undermine his commitment to socialism as a desirable, feasible, and potentially very near future. McCabe lays out Mill's core commitments to utility, security, progress, liberty, equality and fraternity, tying together elements from across Mill's oeuvre to show how he tried to balance these principles in his unique form of socialism. Mill's commitment to decentralised socialism; to cooperation and democratised work-places; to fairer distributions of leisure and opportunities for self-development; to distributive justice, relational egalitarianism, women's empowerment and the environment are critically relevant today as we look to rebuild the world in the wake of financial crises, climate change, and global pandemics. He offers a socialist road so-far not travelled, which it is high time we explored. "--