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.

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.’

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.

When it first appeared in France, Anti-Oedipus was hailed as a masterpiece by some and "a work of heretical madness" by others. In it, Gilles Deleuze and Félix Guattari set forth the following theory: Western society's innate herd instinct has allowed the government, the media, and even the principles of economics to take advantage of each person's unwillingness to be cut off from the group. What's more, those who suffer from mental disorders may not be insane, but could be individuals in the purest sense, because they are by nature isolated from society.

Sartre's greatest novel and existentialism's key text, now introduced by James Wood, and read by the inimitable Edoardo Ballerini. Nausea is the story of Antoine Roquentin, a French writer who is horrified at his own existence. In impressionistic, diary form, he ruthlessly catalogs his every feeling and sensation.

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.

This classic, definitive account of totalitarianism traces the emergence of modern racism as an "ideological weapon for imperialism", beginning with the rise of anti-Semitism in Europe in the 19th century and continuing through the New Imperialism period from 1884 to World War I.

This collection, read by Audie award-winning narrators, includes unabridged recordings of 11 of the most renowned, widely-read, and essential philosophical works from Ancient Greece and Asia to 19th century America, including Meditations, The Republic, and more.

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.

Man and His Symbols owes its existence to one of Jung's own dreams. The great psychologist dreamed that his work was understood by a wide public, rather than just by psychiatrists, and therefore he agreed to write and edit this fascinating book. Here, Jung examines the full world of the unconscious, whose language he believed to be the symbols constantly revealed in dreams.

Published first in 1912, Psychology of the Unconscious was one of the most important stepping stones in the development of Jung’s thought and practice. It has a long subtitle: A Study of the Transformations and Symbolisms of the Libido. A Contribution to the History of the Evolution of Thought. This expressed the underlying impetus - a break from the view of the libido and its functions as taught by Sigmund Freud, which Jung had earlier adopted. It was from this point that the two approaches, which came to be known as the Swiss and Viennese schools, emerged.

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.

In the Upanishads, illumined sages share flashes of insight, the results of their investigation into consciousness itself. In extraordinary visions, they experience directly a transcendent Reality which is the essence, or Self, of each created being. They teach that each of us, each Self, is eternal, deathless, one with the power that created the universe.

Summa Theologica consists of three main parts. The second part is divided two, and this recording presents Prima Secundae - Part I of Part II. Taken in its entirety, Summa Theologica forms an essential contribution to the canon of Catholic doctrine and was written in the last decade of his life by Thomas Aquinas (1225-1274), an Italian-born Dominican friar. Although he died before completing it, the body of thought it contains is a continuing influence to the education and guidance of students of theology in the main Christian traditions.

In the 21st century, Carl Gustav Jung (1875-1961) remains one of the key figures in the field of analytical psychology - and Psychological Types, or The Psychology of Individuation, published in 1921, is one of his most influential works. It was written during the decade after the publication of Psychology of the Unconscious (1912), which effectively ended his friendship and collaboration with Sigmund Freud.