John Stuart Mill expressed many of the central tenets of liberalism with unsurpassed clarity and enduring influence. Yet Mill's apparent victory in the marketplace of ideas has numbed us to the power of his arguments. To many readers today, his views can seem utterly familiar, even banal. Sharing insights from teaching Mill for many years, the eminent philosopher Philip Kitcher makes a cogent case for why we should read this nineteenth-century thinker now. He portrays Mill as a conflicted humanist who wrestled with problems that are equally urgent in our own time. Kitcher reflects on Mill's ideas in the context of contemporary ethical, social, and political issues such as COVID mandates, gun control, income inequality, gay rights, and climate change. More broadly, he shows, Mill's writings help us cultivate our own capacities for critical thought and ethical decision making. Inviting readers into a conversation with Mill, this book shows that he supplies tools for thinking that are as valuable today as they were in the nineteenth century.