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. 

Being and Time was published in 1927 during the Weimar period in Germany, a time of political, social and economic turmoil. Heidegger himself did not escape the pressures and his nationalism, and undeniable anti-Semitism in the following decades cast a shadow over the man, but not the work. Being and Time is not coloured by expressions of his later views (unlike other writings) and remains an outstanding document.  

Perhaps one of the most revolutionary works of philosophy ever presented, The Phenomenology of Spirit is Hegel's 1807 work that is in numerous ways extraordinary. A myriad of topics are discussed, and explained in such a harmoniously complex way that the method has been termed Hegelian dialectic. Ultimately, the work as a whole is a remarkable study of the mind's growth from its direct awareness to scientific philosophy, proving to be a difficult yet highly influential and enduring work.

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.

Published in 1797, the Critique of Pure Reason is considered to be one of the foremost philosophical works ever written. In the Critique of Pure Reason, Immanuel Kant explores the foundation of human knowledge and its limits, as well as man's ability to engage in metaphysics.

Schopenhauer was just 30 when his magnum opus, Die Welt als Wille und Vorstellung, a work of considerable learning and innovation of thought, first appeared in 1818.

Much to his chagrin and puzzlement (so convinced was he of its merits), it didn't have an immediate effect on European philosophy, views and culture. It was only decades later that it was recognised as one of the major intellectual landmarks of the 19th century.

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.

Aristotle's Metaphysics was the first major study of the subject of metaphysics - in other words, an inquiry into 'first philosophy', or 'wisdom'. It differs from Physics which is concerned with the natural world: things which are subject to the laws of nature, things that move and change, are measurable. In Metaphysics, the study falls on 'being qua being' - being insofar as it is being; the causes and principles of being, the causes and principles of substances.

Philosophy of Mind is the third and final part of the Encyclopaedia of the Philosophical Sciences, the collection in which Hegel (1730-1831) offered an overview of his life’s work. Though originally written in 1817, he revised it in 1830, thus providing a finished form the year before his death. Hegel used the three parts of the Encyclopaedia - Science of Logic, Philosophy of Nature and Philosophy of Mind - as a basis for lectures at the Universities of Heidelberg which he joined in 1816, and in Berlin in 1820. 

John Locke and his works - particularly An Essay Concerning Human Understanding - are regularly and rightly presented as foundations for the Age of Enlightenment. His primary epistemological message - that the mind at birth is a blank sheet waiting to be filled by the experiences of the senses - complemented his primary political message: that human beings are free and equal and have the right to envision, create and direct the governments that rule them and the societies within which they live.

This Leibniz collection contains some of the philosopher’s most important works and ideas, spans three decades and illuminates the fascinating intellectual journey undertaken by him in his quest for truth. A prodigious polymath, Leibniz was a mathematician, philosopher, physicist and statesman and engaged with a sweeping range of ideas and disciplines, striving throughout his life to be at the cutting edge of scientific thinking. These Principal Essays are arranged in chronological order. 

Nietzsche never recovered from his mental breakdown in 1889 and therefore was unable to further any plans he had for the ‘magnum opus’ he had once intended, bringing together in a coherent whole his mature philosophy. It was left to his close friend Heinrich Köselitz and his sister Elizabeth Förster-Nietzsche to go through the remaining notebooks and unpublished writings, choosing sections of particular interest to produce The Will to Power, giving it the subtitle An Attempted Transvaluation of All Values. 

Elements of The Philosophy of Right, a key work in the output of Georg Wilhelm Hegel (1770-1831), appeared in 1820 - and was arguably his last major publication. His intention was to state his views on the philosophy of law, political and social theory and ethics. Appearing as it did in a crucial time for the Prussian state - still affected by the Napoleonic wars and their aftermath - it was viewed differently by those on both the left and the right of the political spectrum. 

In 1929, Martin Heidegger (1889-1976) published his remarkable book Kant and the Problem of Metaphysics. The Kantbuch, as Heidegger often called it, is regarded by many as a vital supplement to the unfinished second part of Heidegger’s most influential work, Being and Time, which was published two years earlier in 1927. 

Matter and Memory, (Matière et Mémoire), published in 1896, was the second book written by Henri Bergson (1859-1941), one of the leading French philosophers of his age. It followed Time and Free Will (1889) and helped to establish him as a major force in anti-mechanistic thought, opposing the trend towards uncompromisingly secular and scientific views. However, when Matter and Memory appeared, Bergson was 39 and had yet to become the hugely influential figure he became in the first decades of the 20th century. 

This seminal text in the history of moral philosophy elaborates the basic themes of Kant's moral theory, gives the most complete statement of his highly original theory of freedom of the will, and develops his practical metaphysics. This new edition, prepared by an acclaimed translator and scholar of Kant's practical philosophy, presents the first new translation of the work to appear for many years, together with a substantial and lucid introduction.

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.

As intriguing today as when it was first published, Hume's An Enquiry Concerning Human Understanding is a fascinating exploration into the nature of human knowledge. Using billiard balls, candles, and other colorful examples, Hume conveys the core of his empiricism - that true knowledge can be gained only through sensory experience.

A Treatise of Human Nature is the first work ever published by David Hume, a man who revolutionized our understanding of philosophy. Hume was an advocate of the skeptical school of philosophy and a key figure in the Scottish Enlightenment. He looks at the nature of human experience and cognition, showing that philosophy and reason can only be reflections of our nature.

Two contrasting reflections by Aristotle which cover very particular ground. In 'On the Soul', Aristotle presents his view of the 'life essence' which, he argues, is possessed by living things whether plants, animals or humans. Not a 'soul' in the generally accepted Western use of the term, this 'soul', he says, is a life force that is indivisible from the organism that possesses it.

In this delightfully lucid and accessible audiobook, America’s foremost philosopher, Mortimer J. Adler, explores 10 errors in the development of modern thought and examines the serious consequences they have in our everyday lives. Some of these mistakes include: (1) The mistake of identifying happiness with a good time rather than with that which is good for us; (2) The failure to differentiate between the perceptual and the conceptual realms of thought, by which the human mind is distinguished from the animal mind; and (3) The failure to acknowledge free will, which leads to the rejection of moral responsibility.

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.

Considered by many to be Hannah Arendt's greatest work, published as she neared the end of her life, The Life of the Mind investigates thought itself, as it exists in contemplative life. In a shift from her previous writings, most of which focus on the world outside the mind, this work was planned as three volumes that would explore the activities of the mind considered by Arendt to be fundamental. What emerged is a rich, challenging analysis of human mental activity, considered in terms of thinking, willing, and judging.    

Benedict de Spinoza's Ethics, first published in 1677, constitutes a major systematic critique of the traditional and religious foundations of philosophical thought. In it, Spinoza follows a logical step-by-step format consisting of definitions, axioms, propositions, proofs, and corollaries to create a comprehensive inquiry into the truth about God, nature, and humans' place within the universe. From these broad metaphysical themes, Spinoza derives what he considered to be the highest principles of religion and society and lays out an ethical system in which reason is the supreme value.

John Locke and his works - particularly An Essay Concerning Human Understanding - are regularly and rightly presented as foundations for the Age of Enlightenment. His primary epistemological message - that the mind at birth is a blank sheet waiting to be filled by the experiences of the senses - complemented his primary political message: that human beings are free and equal and have the right to envision, create and direct the governments that rule them and the societies within which they live.

A Short History of Ethics is a significant contribution written by one of the most important living philosophers. It remains an important work, ideal for all students interested in ethics and morality.

There is a cause, or a reason, behind everything that happens. This is the fundamental view behind the classical proposition the Principle of Sufficient Reason, which, in 1813, Schopenhauer chose as his subject for further examination in his doctoral dissertation On the Fourfold Root of the Principle of Sufficient Reason....

Schopenhauer was just 30 when his magnum opus, Die Welt als Wille und Vorstellung, a work of considerable learning and innovation of thought, first appeared in 1818.

Much to his chagrin and puzzlement (so convinced was he of its merits), it didn't have an immediate effect on European philosophy, views and culture. It was only decades later that it was recognised as one of the major intellectual landmarks of the 19th century.

First published in 1930, Civilization and Its Discontents is one of the most influential works of pioneering psychologist Sigmund Freud. Focusing on the tension between the primitive drives of the individual and the demands of civilization for order and conformity, Freud draws upon his psychoanalytic theories to explain the fundamental structures, conflicts, and consequences of society.

This brilliantly conceived book is based on a lecture course given by Dr. Leonard Peikoff in 1976 entitled, "The Philosophy of Objectivism". The lectures were attended by Ayn Rand, who helped prepare them and wh