John Stuart Mill is often seen as an important figure in the transition from the classical liberalism of the seventeenth and eighteenth centuries to the more egalitarian, social welfare form of liberalism that emerged in response to the effects of the Industrial Revolution later in twentieth-century Britain. For our purposes, however, it is perhaps more significant to highlight Mill's role as a kind of culmination of classical liberal political economy. In Mill's political and economic writings, we see both direct linkages back to the rights and interest-based conceptual nerve centre of classical liberalism, as well as a fuller development of the early liberal response to socialism and communism we first encountered in Paine's Agrarian Justice. Mill is also arguably the last British thinker to offer a comprehensive philosophy including rigorous and systematic reflections on politics, ethics, morality, aesthetics, economics, logic and culture. An unparalleled intellectual provocateur, Mill was the epitome of the philosopher engagé who spent many decades publicly commenting on political and philosophical controversies in a variety of journals and newspapers, and even served a three-year term in Parliament as the MP for Westminster.

Today Mill is probably best known as the author of On Liberty (1859), one of the seminal texts in the liberal tradition of free speech, personal autonomy and pluralism. However, in his time Mill was at least as famous for his writings on political economy, especially his massive Principles of Political Economy (1848), which passed through more than a half dozen editions in Mill's lifetime and became established as the classic textbook of British political economy for decades until the appearance of Alfred Marshall's 1890 Principles of Economics. The principle of individual freedom as the requirement for the full development of human character underlies Mill's political economy as fully as it does every other aspect of his thought. It is perhaps hardly surprising that the same thinker who proclaimed in On Liberty that ‘over himself, over his own body and mind, the individual is sovereign’, would have professed earlier in his economic writings that ‘there is a part of the life of every person who has come to years of discretion within which the individuality of that person ought to reign uncontrolled either by any other individual or by the public collectively’.