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.

Though Twilight of the Idols (written in a week in 1888 and subtitled How to Philosophise with a Hammer) came near the end of Nietzsche’s creative life, he actually recommended it as a starting point for the study of his work. This was because from the beginning he viewed it as an introduction to his wide-ranging views.

The Science of Rights (originally in German: Grundlage des Naturrechts nach Principien der Wissenschaftslehre) by Johann Gottlieb Fichte, was originally written in 1796 and later translated by Adolph Ernst Kroeger into English.

Though published in 1867 when the British Empire was approaching its height, Walter Bagehot’s essay "The English Constitution" is not only one of the great political classics but is also an unquestionably relevant document for our times. Despite the passing of more than 150 years, despite huge changes in enfranchisement, in attitudes and in world order, this fascinating document prompts us to re-evaluate the process of government - wherever we live. And what is more, it is written with grace, elegance - and wit!

Underlain by an acute sense of ethics, this provided the basis for his strongly declared, wide-ranging views on many subjects: prohibition of cock-fighting, liberty of the press, universal suffrage, the removal of religious tests for office and even hunting. All were radical ideas for his time. He also proposed the decriminalisation of homosexuality, though even he did not dare to publish his essay on this subject during his lifetime. But An Introduction to the Principles of Morals and Legislation was his major work.

Proclus - or Proclus of Athens, as he is sometimes known - is widely and rightly considered to be one of the most significant later Neoplatonist philosophers. At age 40 (c.437 CE) or so, Proclus became head of the revived Plato’s Academy in Athens. In his role for the next 50 years, the unmarried Proclus worked hard, combining effectively the roles of administrator, teacher and writer. Astronomy, ethics, mathematics, physics, theology - Proclus tackled all of those topics that together fell under the umbrella of philosophy in his time.

Plotinus, born in Lycopolis, Egypt, when it was part of the Roman Empire, was a major figure in the philosophical school later called Neoplatonism. Neoplatonists viewed reality as deriving from a single force or figure expressed as 'the One'. Two further concepts from Plotinus, 'the Intellect' and 'the Soul', are also principal features of his philosophy. These proposals led to the work of Plotinus forming a bridge between Plato and the monotheistic religions of Christianity, Judaism and Islam as well as Gnosticism.

Attention is not just receptive, but actively creative of the world we inhabit. How we attend makes all the difference to the world we experience. And nowadays in the West we generally attend in a rather unusual way: governed by the narrowly focused, target-driven left hemisphere of the brain.

The four books of the Summa contra Gentiles were written by Thomas Aquinas between 1259-1265, before the considerably larger and more influential, Summa Theologica. The purpose of each work was different. Whereas the Summa Theologica addressed the faithful, especially theology students, the intention of the Summa Contra Gentiles (Systematic Exposition Against Non-Christians) was to speak to a non-aligned and even hostile audience. To that purpose, Aquinas presented arguments ‘refuting specific beliefs or heresies.'