John Stuart Mill's resolute dedication to the cause of freedom inspired this 1859 treatise. Discussed and debated from time immemorial, the concept of personal liberty went without codification until the publication of this enduring work which applies an ethical system of utilitarianism to society and the state which to this day remains well known and studied.

Mills (1806-1873), a British economist, philosopher, and ethical theorist whose argument does not focus on "the so-called Liberty of the Will…but Civil, or Social Liberty: the nature and limits of the power which can be legitimately exercised by society over the individual" asks and answers provocative questions relating to the boundaries of social authority and individual sovereignty. He declares that there is "one very simple principle" regarding the use of coercion in society — one may only coerce others either to defend oneself or to defend others from harm.

Mill puts forth his basic argument in favor of liberty for the individual as long as it harms no one else. Setting forth the value of liberty of opinion and liberty of action, he emphasizes the importance of individuality versus the "tyranny of the majority" and highlights the positive effects of liberty on all people and on society, as freedom enables progress and prevents social stagnation. He details the appropriate level of authority society ought to have over the individual society’s obligation to protect people incapable of exercising their own freedom. On Liberty remains one of the most influential studies on the nature of individual liberty and its role in a democratic society.