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. 

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.

Kant's Prolegomena, although a small book, is without doubt the most important of his writings, writes the translator, Paul Carus. Prolegomena means, literally, prefatory or introductory remarks, and it furnishes us with a key to his main work, The Critique of Pure Reason; in fact, it is an extract containing all the salient ideas of Kant's system. It approaches the subject in the simplest and most direct way and is therefore best adapted as an introduction into his philosophy. 

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 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.

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.

Philosophical Investigations was published in 1953, two years after the death of its author. In the preface written in Cambridge in 1945 where he was professor of philosophy he states: ‘Four years ago I had occasion to re-read my first book (the Tractatus Logico-Philosophicus) and to explain its ideas to someone. It suddenly seemed to me that I should publish those old thoughts and the new ones together: that the latter could be seen in the right light only by contrast with and against the background of my old way of thinking.’

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.

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.

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.

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. 

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. 

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.