Question: In which publication did the great 19ty-century liberal philosopher John Stuart Mill explain the harm principle, of exercising power over others only to protect them from harm?

Context paragraphs:
Informed judge: The informed judge is a concept that 19th-century political philosopher John Stuart Mill used when describing utilitarianism.  Mill posited that in order to find the better of two choices, one must find the choice that yields more happiness.  One does so, according to Mill, by finding an informed judge, who is simply someone who has experienced both options, and whichever choice the informed judge prefers will presumably be the better one.

The Limits of State Action: The Limits Of State Action is a philosophical treatise by Wilhelm von Humboldt, which is a major work of the German Enlightenment and the most significant source for the ideas which John Stuart Mill popularized in his essay "On Liberty".  Humboldt defines the criteria by which the permissible limits of the state's activities may be determined.  His basic principle, like that of Mill, is that the only justification for government interference is the prevention of harm to others.  He discusses in detail the role and limits of the state's responsibility for the welfare, security and morals of its citizens.

Harm principle: The harm principle holds that the actions of individuals should only be limited to prevent harm to other individuals.  John Stuart Mill articulated this principle in "On Liberty", where he argued that, "The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others."  An equivalent was earlier stated in France's "Declaration of the Rights of Man and of the Citizen" of 1789 as, "Liberty consists in the freedom to do everything which injures no one else; hence the exercise of the natural rights of each man has no limits except those which assure to the other members of the society the enjoyment of the same rights.  These limits can only be determined by law."

Liberal corporatism: Liberal corporatism refers to the application of economic corporatism by liberal political parties and organizations, that recognizes the bargaining interests of multiple groups within society, such as in the business, labour, and agricultural sectors and licenses them to engage in bargaining over economic policy with the state.  Liberal corporatism is often in conflict from proponents of liberal pluralism that opposes the granting of power to organized interest groups. English liberal philosopher John Stuart Mill supported corporatist-like economic associations as needing to predominate in society to create equality for labourers and give them a voice in management through democratic economic rights.  Unlike a number of other forms of corporatism, liberal corporatism does not reject capitalism or individualism, but believes that the capitalist firm is a social institution that requires its managers to go beyond achieving the bottom line, by recognizing the needs of their members.  This liberal corporatist ethic was similar to Taylorism but called for democratization of the capitalism firm.  Liberal corporatists believed that inclusion of all members in the election of management would bring them into the process of management and in effect "reconcile ethics and efficiency, freedom and order, liberty and rationality".

On Liberty: On Liberty is a philosophical work by the English philosopher John Stuart Mill, originally intended as a short essay.  The work, published in 1859, applies Mill's ethical system of utilitarianism to society and the state.  Mill attempts to establish standards for the relationship between authority and liberty.  He emphasizes the importance of individuality, which he conceived as a prerequisite to the higher pleasures—the "summum bonum" of Utilitarianism.  Furthermore, Mill criticizes the errors of past attempts to defend individuality where, for example, democratic ideals resulted in the "tyranny of the majority".  Among the standards established in this work are Mill's three basic liberties of individuals, his three legitimate objections to government intervention, and his two maxims regarding the relationship of the individual to society.

John Stuart Mill: John Stuart Mill (20 May 1806 – 8 May 1873) was an English philosopher, political economist and civil servant.  One of the most influential thinkers in the history of liberalism, he contributed widely to social theory, political theory and political economy.  Dubbed "the most influential English-speaking philosopher of the nineteenth century", Mill's conception of liberty justified the freedom of the individual in opposition to unlimited state and social control.

Just society: The idea of a just society first gained modern attention when philosophers such as John Stuart Mill asked, "What is a 'just society'?"  Their writings covered several different perspectives including allowing individuals to live their lives as long as they didn't infringe on the rights to others, to the idea that the resources of society should be distributed to all, including those most deserving first.  In 1861, John Stuart Mill published an essay entitled, "Utilitarianism".  In this famous essay, Mill advocated the latter view, in which decision makers attended to the "common good" and all other citizens worked collectively to build communities and programs that would contribute to the good of others.

A System of Logic: A System of Logic, Ratiocinative and Inductive is an 1843 book by English philosopher John Stuart Mill.  In this work, he formulated the five principles of inductive reasoning that are known as Mill's Methods.  This work is important in the philosophy of science, and more generally, insofar as it outlines the empirical principles Mill would use to justify his moral and political philosophies.

John Stuart Mill Institute: The John Stuart Mill Institute is a non-governmental, Heidelberg-based research institute founded in 2009 and named after John Stuart Mill, an influential 19th-century English philosopher and politician.

Helen Taylor (feminist): Helen Taylor (1831–1907) was an English feminist, writer and actress.  She was the daughter of Harriet Taylor Mill and stepdaughter of John Stuart Mill.  After the death of her mother, she lived and worked with John Stuart Mill.  Together they promoted women's rights.  From 1876 to 1884 (when she quit due to her health) she was a member of the London School Board.  In 1881, she joined the Democratic Federation.

Supporting paragraphs: Harm principle John Stuart Mill
Answer: On Liberty