Karl Abraham can be considered one of Sigmund Freud's most creative and devoted disciples, and has been one of the most important voices in the development of psychoanalysis. Despite dying young, his key works provide an invaluable contribution to psychoanalysis as one of its most influential founding fathers.In 1907, he had his first contact with Freud, with whom he developed a lifetime relationship. Returning to Germany, he founded the Berliner Society of Psychoanalysis in 1910. He was the president of the International Psychoanalytical Association from 1914 to 1918 and again in 1925. Abraham collaborated with Freud on the understanding of manic-depressive illness, leading to Freud's paper on 'Mourning and Melancholia' in 1917. He was the analyst of Melanie Klein during 1924-1925, and of a number of other British psychoanalysts, including Edward Glover, James Glover, and Alix Strachey. He was a mentor for an influential group of German analysts, including Karen Horney, Helene Deutsch, and Franz Alexander. His key works cover the areas of the development of child sexuality and its relation to mental disorders, the development of the libido, cultural issues including work on various myths suggesting their relation to dreams (1909), as well as writing an interpretation of the spiritual activities of the Egyptian monotheistic Pharaoh Amenhotep IV (1912).Described by Freud himself as his "best pupil", his work is increasingly recognised for its importance in the development of psychoanalysis. Sigmund Freud was born in 1856 in Moravia; from 1860 until Hitler's invasion of Austria in 1938 he lived in Vienna. He was then forced to seek asylum in London, where he died the following year. He began his career as a doctor, specialising in work on the anatomy and physiology of the nervous system. He was almost thirty when his interests first turned to psychology, and during ten years of clinical work in Vienna he developed the practice of what he called "psychoanalysis". This began simply as a method of treating neurotic patients by investigating their minds, but it quickly grew into an investigation of the workings of the mind in general, both ill or healthy. Freud demonstrated the normal development of the sexual instinct in childhood and, largely on the basis of an examination of dreams, arrived at his fundamental discovery of the unconscious forces that influence our everyday thoughts and actions. Freud's ideas have shaped not only many specialist disciplines, but have also influenced the entire intellectual climate of the last century. Ernst Falzeder, PhD, is a Senior Research Fellow at the University College London, and editor and translator for the Philemon Foundation of the publication of the 'Complete Works of C. G. Jung'. He is a former research fellow at the University of Geneva, as well as Cornell University Medical School (NYC), and Harvard University (Cambridge, MA). He was chief editor of the Freud/Ferenczi correspondence (3 vols., Harvard University Press), editor of the complete Freud/Abraham letters (Karnac), translator of Jung's seminar on children's dreams (Princeton University Press), and editor, with John Beebe, as well as translator of Jung's correspondence with Hans Schmid (Princeton University Press). He has also written more than two hundred publications on the history, theory and technique of psychoanalysis and analytical psychology.