Here are three important but very different Dialogues from the Middle Period. Symposium, the most well-known in this collection, is concerned with the theme of love. In the house of Agathon, a group of friends - each very different in personality and background - meet to consider and discuss various kinds of love. Each one, Phaedrus, Pausanias, Eryximachus, Aristophanes (the playwright) and Agathon (a prize-winning tragic poet), presents his particular view in a short discourse.

Here, in this second collection of Socratic Dialogues from Plato's Early Period, read by David Rintoul as Socrates with a full cast, are contrasting six works. Often, as with Gorgias, which opens the recording, Socrates combats the popular subjects of sophistry and rhetoric, in direct conversation with Gorgias (a leading sophist teacher), and with one of his pupils, Callicles.

Here are the Socratic Dialogues presented as Plato designed them to be - living discussions between friends and protagonists, with the personality of Socrates himself coming alive as he deals with a host of subjects, from justice and inspiration to courage, poetry and the gods. Plato's Socratic Dialogues provide a bedrock for classical Western philosophy. For centuries they have been read, studied and discussed via the flat pages of books, but the ideal medium for them is the spoken word.

These five very different Socratic Dialogues date from Plato's later period, when he was revisiting his early thoughts and conclusions and showing a willingness for revision. In Timaeus (mainly a monologue read by David Timson in the title role), Plato considers cosmology in terms of the nature and structure of the universe, the ever-changing physical world and the unchanging eternal world. And he proposes a demiurge as a benevolent creator God.

The Republic is perhaps the single most important, the most studied and the most quoted text of all of Plato's Socratic Dialogues. Through the medium of Socrates, Plato outlines his view and ideas concerning the ideal working of the city-state. Socrates narrates a conversation that took place the previous day with Cephalus, Glaucon, Thrasymachus and others. The dialogue is organised into 10 books and covers a broad range of topics, including the ideal community and the ideal rulers of the community.

Aristotle’s Nicomachean Ethics and Eudemian Ethics represent, in many ways, the Western classical springboard for the systematic study and implementation of ethics, the optimum behaviour of the individual. (By contrast, Aristotle’s Politics concerns the optimum blueprint for the city-state.) It is in the hands of each individual, he argues in these books on personal ethics, to develop a character which bases a life on virtue, with positive but moderate habits.

Xenophon was a friend of Socrates, and yet his concise memories of the iconic philosopher have lived under the shadow of the more voluminous accounts by Plato. Yet Xenophon’s two works are, in many ways, more entertaining and more accessible, and they present a different view of the man who embodies a clear mind, temperate, ethical living, sharp intellect and humour.

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. 

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. 

The Greek word sumposion means a drinking party (a fact shamefully ignored by the organizers of modern symposia), and the party described in Plato's Symposium is one supposedly given in the year 416 BC by the playwright Agathon to celebrate his victory in the dramatic festival of the Lenaea. He has already given one party, the previous evening; this second party is for a select group of friends, and host and guests alike are feeling a little frail.

Poetics and Rhetoric are the two major works by Aristotle which, after more than 2,000 years, remain key behavioural handbooks for anyone interested in story, performance, presentation and indeed psychology. The continuing influence of Poetics, for example, is readily discernible even among the scriptwriters of Hollywood!

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.

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. 

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.’

The Antichrist and Ecce Homo were two of the last works written by Friedrich Nietzsche just before his mental collapse in 1889. Though both written in 1888, they are very different in content and style. In The Antichrist, Nietzsche expands on his view that the submissive nature of Christianity undermined Western society, depressing and sapping energy.