Continuing where Thus Spoke Zarathustra left off, Nietzsche's controversial work Beyond Good and Evil is one of the most influential philosophical texts of the 19th century and one of the most controversial works of ideology ever written. Attacking the notion of morality as nothing more than institutionalised weakness, Nietzsche criticises past philosophers for their unquestioning acceptance of moral precepts. Nietzsche tried to formulate what he called "the philosophy of the future".

In the Nicomachean Ethics (so called after their first editor, Aristotle's son Nicomachus) Aristotle sets out to discover the good life for man: the life of happiness or eudaimonia. Happiness for Aristotle is the activity of the soul in accordance with virtue. Virtue is shown in the deliberate choice of actions as part of a worked-out plan of life, a plan which takes a middle course between excess and deficiency.

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.

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.

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his close friend Heinrich Köselitz and his sister Elizabeth Förster-Nietzsche to go through the remaining notebooks and unpublished writings, choosing sections of particular interest to produce The Will to Power, giving it the subtitle An Attempted Transvaluation of All Values.

In On the Genealogy of Morals, subtitled "A Polemic", Nietzsche furthers his pursuit of a clarity that is less tainted by imposed prejudices. He looks at the way attitudes towards 'morality' evolved and the way congenital ideas of morality were heavily colored by the Judaic and Christian traditions.

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.

The Gay Science (The Joyful Wisdom) is one of Nietzsche's greatest books. His wonderfully fertile mind roams over mankind, his thoughts, his emotions, his behaviour and his weaknesses with remarkable clarity, with insight - but also with humour!In this work are 383 separate paragraphs, some short, some long, but all singular observations - the epitome of his famous aphoristic style. 'Morality is the herd instinct in the individual.'

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.

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.

Viktor E. Frankl was a medical doctor at a psychiatric hospital in 1942 when he became a prisoner in Nazi concentration camps in World War II. In 1946, he published this book about his camp experiences and a method of psychotherapy he developed. Forty-five years later, it was still named one of the most influential books in the United States. Part One describes his three years in four Nazi concentration camps, which took the lives of his wife, father, mother, and brother. He closely observed inmates’ reactions to their situation, as well as how survivors came to terms with their liberation.

A century after it first appeared, Crime and Punishment remains one of the most gripping psychological thrillers. A poverty-stricken young man, seeing his family making sacrifices for him, is faced with an opportunity to solve his financial problems with one simple but horrifying act: the murder of a pawnbroker. She is, he feels, just a parasite on society. But does the end justify the means? Rodion Romanovitch Raskolnikov makes his decision and then has to live with it.

In 81 brief chapters, Lao Tzu's Tao Te Ching, or Book of the Way, provides advice that imparts balance and perspective, as well as a serene and generous spirit. It teaches us how to work for the good with the effortless skill that comes from being in accord with the Tao: the basic principle of the universe.

One of the most influential works of this century, The Myth of Sisyphus and Other Essays is a crucial exposition of existentialist thought. Influenced by works such as Don Juan and the novels of Kafka, these essays begin with a meditation on suicide; the question of living or not living in a universe devoid of order or meaning.