Mill predicted that “[t]he Liberty is likely to survive longer than anything else that I have written … because the conjunction of [Harriet Taylor’s] mind with mine has rendered it a kind of philosophic text-book of a single truth, which the changes progressively taking place in modern society tend to bring out in ever greater relief.” Indeed, On Liberty is one of the most influential books ever written, and remains a foundational document for the understanding of vital political, philosophical and social issues. In addition to its many useful appendices, this new edition includes a chronology, bibliography, and a substantial introduction which outlines Mill’s life and works, and sets this central work of 1859 in the context of both his own intellectual development and of the play of ideas and political forces in Victorian society.