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.

Thomas Mann's last great novel, first published in 1947 and now newly rendered into English by acclaimed translator John E. Woods, is a modern reworking of the Faust legend, in which Germany sells its soul to the Devil. Mann's protagonist, the composer Adrian Leverkühn, is the flower of German culture, a brilliant, isolated, overreaching figure, his radical new music a breakneck game played by art at the very edge of impossibility. In return for twenty-four years of unparalleled musical accomplishment, he bargains away his soul—and the ability to love his fellow man.

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.

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 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 two foes of human happiness are pain and boredom.' Arthur Schopenhauer (1788-1860) was one of the most influential philosophers of the 19th century because his humanistic, atheistic, if pessimistic views chimed with a new secularism that was emerging from a Western society dominated by religion. Despite his rather forbidding image (and a few outdated views), he is one of the most approachable German philosophers, and this is certainly evident in these two key works, The Wisdom of Life and Counsels and Maxims.

The rivalry between two of the dominant city states of Ancient Greece, Athens and Sparta, erupted into a war lasting nearly 30 years and was to have a dramatic effect on the balance of power in the area. Between 431 and 404 BCE, the two cities battled it out on land and sea, aided by their alliances with neighbouring states: Athens’ Delian League vigorously opposed Sparta’s Peloponnesian League in a conflict which effectively involved the whole region.

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.

Plotinus (204/5 -270 CE), 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.

Beyond the rehashed clichés, this book inspires us to rediscover Diogenes' philosophical legacy—whether it be the challenge to the established order, the detachment from materialism, the choice of a return to nature, or the formulation of a cosmopolitan ideal strongly rooted in the belief that virtue is better revealed in action than in theory.

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.'

Though born to a poor but pious family of ribbon weavers in Saxony in 1762, Johann Gottlieb's exceptional intelligence was apparent from an early age. Remarkably, from this humble background, he earned himself a respected place in the pantheon of late 18th and early 19th century German philosophers. In the 20th and 21st century, his importance and contribution to Western philosophy has been increasingly acknowledged. There are two substantial lecture series and one essay stemming from his time in Berlin in Popular Works Volume 2: much of Fichte's important work appeared initially in lectures.