The writings of John Stuart Mill have become the cornerstone of political liberalism. Collected in this volume are John Stuart Mill's Four seminal and most widely read works: On Liberty, The Subjection of Women, Utilitarianism and Socialism.

Mill's conception of liberty (from his most famous book, On Liberty) justified the freedom of the individual in opposition to unlimited state control.

The Subjection of Women is a passionate defense of the rights of women from the point of view of a man that truly believes in equality.

In Utilitarianism, Mill's major contribution is his argument for the qualitative separation of pleasures, in response to Jeremy Bentham's formulation of utilitarianism: the "greatest-happiness principle", which holds that one must always act so as to produce the greatest aggregate happiness among all sentient beings, within reason.

Socialism is an early attempt of visualizing a way of putting the Marxist theory into practice. Mill realizes that distributing the wealth onto the proletariat will lead to a state of routine work, where there is neither motivation nor anxiety, not realizing, however, that routine will devoid performance of excellence.

John Stuart Mill has been called "the most influential English-speaking philosopher of the nineteenth century."