What are the most common dreams and why do we have them? What does a dream about death mean? What do dreams of swimming, failing, or flying symbolize? First published by Sigmund Freud in 1899, The Interpretation of Dreams considers why we dream and what it means in the larger picture of our psychological lives.

Here are three key works by Sigmund Freud which, published in the first decades of the 20th century, underpinned his developing views and had such a dramatic effect on world society. In the uncompromising Three Essays on the Theory of Sexuality (1905), he declared that 'sexual aberrations' are not limited to the insane but exist in 'normal' people to a greater or lesser degree. The three essays are divided between sexual perversions, childhood sexuality and puberty.

The Interpretation of Dreams by Sigmund Freud is one of the most significant books of the 20th century. Though dreams and their role in human consciousness have been a continuing thread in religion and art and life down the centuries, Freud's look at the subject through the prism of his emerging practice and study of psychoanalysis provided a startlingly new and challenging perspective.

The Psychopathology of Everyday Life, which appeared first in 1901 and was then expanded in a series of subsequent editions, has proved to be one of Freud's most popular works, and one of his most influential during his lifetime. It was here that he proposed that many slips and errors of memory common to the average man in everyday life actually signals unconscious issues that beset the individual, and, if examined, can be extremely revealing.

Sigmund Freud (1856-1939) is remembered as the father of psychoanalysis. Civilization and Its Discontents (1930) is one of his key works, written three decades after his seminal book The Interpretation of Dreams. In it he considers the conflict between the needs of the individual acting both egotistically and altruistically in the pursuit of happiness and the myriad demands of civilised society and the ensuing tensions this clash of needs and demands generates.

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.

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.

This collection of 11 wide-ranging lectures which appeared originally in 1933, was based on lectures previously given when Jung was in the process of absorbing a considerable period of study of Eastern religions, Gnosticism and other religious sources. It was a time, according to the translator Cary F. Baynes, ‘when the Western world stands on the verge of a spiritual rebirth...after a long period of outward expansion, we are beginning to look inside ourselves once more.’

As the 20th century drew to a close, the Austrian psychologist Alfred Adler (1870-1937) was perhaps the least known of the prominent figures of his time - in particular Sigmund Freud and Carl Gustav Jung - and yet he continues to be a figure of influence in the 21st century. His school of ‘individual psychology’ involved a holistic approach to the study of the individual, with a key focus on the way each person viewed the world, especially regarding their concerns of inferiority.

Alfred Adler was an Austrian physician, psychotherapist, and one of the founding fathers of modern psychology. In Understanding Human Nature, (1928), Adler sets out to acquaint the general public with the basics of Individual Psychology, which holds that the driving force of human behavior is the individual’s striving for power, partly to compensate for feelings of inferiority. The purpose of the book is to identify mistaken behaviors and show how they undermine healthy relationships, in order to gently guide the individual towards adjustment.

In this best-selling book, one of America's most distinguished psychologists crystallises the great progress that has been made in the development of the techniques and basic philosophy of counselling. Carl Rogers gives a clear exposition of procedures by which individuals who are being counselled may be assisted in achieving for themselves new and more effective personality adjustments. Contemporary psychology derives largely from the experimental laboratory or from Freudian theory. It is preoccupied with minute aspects of animal and human behaviour or with psychopathology.

This substantially revised fifth edition of a classic text includes an updated preface, new content on the therapeutic relationship, substantially revised chapters on the middle phase of counselling and reflections on the influence of other modalities and shared aspects of practice across approaches. Each chapter now includes an annotated further listening section to help deepen knowledge and reinforce learning of key aspects of the counselling process.

Friedrich Nietzsche (1844-1900) has influenced philosophers such as Martin Heidegger, Jean-Paul Sartre, Oswald Spengler, George Grant, Emil Cioran, Albert Camus, Ayn Rand, Jacques Derrida, Leo Strauss, Max Scheler, Michel Foucault and Bernard Williams. His writings on aesthetics, language, truth, morality, cultural theory, history, nihilism, power, and the meaning of existence have exerted a vast influence on Western philosophy and intellectual history.

Collected Papers on Analytical Psychology comprises a selection of key writings and lectures by Carl Gustav Jung produced between 1902 and 1916, which are presented in chronological order. As such they provide a fascinating exposition of the nature and essence of the psychological content of psychoses and neuroses, as explored and discovered by Dr Jung in the early years of his long and distinguished career.

Modern Man in Search of a Soul is the classic introduction to the thought of Carl Jung. Along with Freud and Adler, Jung was one of the chief founders of modern psychiatry. In this book, Jung examines some of the most contested and crucial areas in the field of analytical psychology: dream analysis, the primitive unconscious, and the relationship between psychology and religion.