An Analysis of the Theoretical and Clinical Contribution of the Father of Psychoanalysis Abstract This article provides a systematic overview of the thought of Sigmund Freud (1856–1939), founder of psychoanalysis and one of the most influential intellectual figures of the 20th century. The main theoretical cores of his work are examined: the topographic and structural model of the mind, the theory of psychosexual development, the clinical technique of free association and dre