This expanded edition of John Stuart Mill's Utilitarianism includes the text of his 1868 speech to the British House of Commons defending the use of capital punishment in cases of aggravated murder. The speech is significant both because its topic remains timely and because its arguments illustrate the applicability of the principle of utility to questions of large-scale social policy.

Immanuel Kant’s Critique of Pure Reason can lay claim to being the most important single work of modern philosophy, a work whose methodology, if not necessarily always its conclusions, has had a profound influence on almost all subsequent philosophical discourse. In this work Kant addresses, in a groundbreaking elucidation of the nature of reason, the age-old question of philosophy: “How do we know what we know?” and the limits of what it is that we can know with certainty.

Aristotle's Nicomachean Ethics, said to be dedicated to Aristotle's son, Nicomachus, is widely regarded as one of the most important works in the history of Western philosophy. Addressing the question of how men should best live, Aristotle's treatise is not a mere philosophical meditation on the subject, but a practical examination that aims to provide a guide for living out its recommendations.

Kant published this work in 1795, during the aftermath of the American Revolution and the French Revolution. The high hopes of the European Enlightenment had been dampened by the Reign of Terror in which tens of thousands of people died, and the perpetual cycle of war and temporary armistice seemed to be inescapable. Kant's essay is best known as an early articulation of the idea of a league of nations that could bring an end to all hostilities. Today, the United Nations continues to pursue that dream, but lasting peace still seems to be wishful thinking.

Groundwork of the Metaphysics of Morals is the first of Immanuel Kant's mature works on moral philosophy and remains one of the most influential in the field. Kant conceives his investigation as a work of foundational ethics - one that clears the ground for future research by explaining the core concepts and principles of moral theory, and showing that they are normative for rational agents.

In On the Genealogy of Morals, subtitled "A Polemic", Nietzsche furthers his pursuit of a clarity that is less tainted by imposed prejudices. He looks at the way attitudes towards 'morality' evolved and the way congenital ideas of morality were heavily colored by the Judaic and Christian traditions.

Immanuel Kant's Fundamental Principles of the Metaphysics of Morals, first published in 1785, lays out Kant's essential philosophy and defines the concepts and arguments that would shape his later work. Central to Kant's doctrine is the categorical imperative, which he defines as a mandate that human actions should always conform to a universal, unchanging standard of rational morality.

The Critique of Practical Reason was published in 1788, seven years after Immanuel Kant's major work, Critique of Pure Reason. In it, Kant sets out his moral philosophy - and it proved a seminal text in the history of the subject. He argues that the summum bonum (the highest good) of life is that rather than just pursuing happiness, people should inhabit a moral dimension that enables them to deserve the happiness that God can give. Though much shorter than Critique of Pure Reason, this is the sourcebook for Kant’s ethical doctrines.

Critique of Judgement was published in 1790 and is divided into two parts, the Critique of Aesthetic Judgement and the Critique of Teleological Judgement. Our ‘judgements of taste’, as Kant describes our aesthetic judgements, have both a personal and a universal function: personal, because we have a subjective aesthetic response to the ‘agreeable’, the ‘beautiful’, the ‘sublime’ and the ‘good’; but also there is a ‘universal’ aspect because our aesthetic response has a ’disinterested’ element. This brings under Kant’s spotlight, for example, the concept of beauty and the perception of beauty.

From the perspective of an unbeliever, Fear and Trembling explores the paradox of faith, the nature of Christianity, and the complexity of human emotion. Kierkegaard examines the biblical story of Abraham, who was instructed to sacrifice his son Isaac, and forces us to consider Abraham's state of mind. What drove Abraham, and what made him carry out such an absurd and extreme request from God? Kierkegaard argues that Abraham's agreement to sacrifice Isaac, and his suspension of reason, elevated him to the highest level of faith.

The leviathan is the vast unity of the State. But how are unity, peace, and security to be attained? Hobbes’ answer is sovereignty, but the resurgence of interest today in Leviathan is due less to its answers than its methods: Hobbes sees politics as a science capable of the same axiomatic approach as geometry.

First published in 1859, John Stuart Mill's On Liberty is an exhaustive exploration of social and civic liberty, its limits, and its consequences. Mill's work is a classic of political liberalism that contains a rational justification of the freedom of the individual in opposition to the claims of the state.

John Stuart Mill (1808-1873) was a torchbearer for liberal thought in the 19th century, including liberty of the individual and freedom of speech, and he championed women's suffrage in Parliament. A remarkable man - he learned Greek aged three and at eight had read Herodotus, Xenophon and Plato - he campaigned all his life for a just society. These two essays are his key works.

One of the most influential works of this century, The Myth of Sisyphus and Other Essays is a crucial exposition of existentialist thought. Influenced by works such as Don Juan and the novels of Kafka, these essays begin with a meditation on suicide; the question of living or not living in a universe devoid of order or meaning.

Continuing where Thus Spoke Zarathustra left off, Nietzsche's controversial work Beyond Good and Evil is one of the most influential philosophical texts of the 19th century and one of the most controversial works of ideology ever written. Attacking the notion of morality as nothing more than institutionalised weakness, Nietzsche criticises past philosophers for their unquestioning acceptance of moral precepts. Nietzsche tried to formulate what he called "the philosophy of the future".