This series of 28 lectures was given by Sigmund Freud (1856-1939), the founder of psychoanalysis, during the First World War and first published in English in 1920. The purpose of this general introduction was to present his work and ideas - as they had matured at that point - to a general public; and even though there was to be considerable development and change over the ensuing years, these talks still offer a valuable and remarkably approachable entry point to his revolutionary concepts.

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.

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.

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.

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".