German psychiatrist and psychologist, known as the creator of a typology of temperaments based on body type. He developed a classification of types of human constitution into athletic, asthenic and pycnic, linking physical characteristics with character traits and predisposition to mental disorders. His central work was the book “Body Structure and Character” (1921). Kretschmer was also engaged in research in the field of psychotherapy, child psychopathology, and developed hypnosis techniques. He was a professor and director of a clinic at the universities of Marburg and Tübingen, where he created an experimental psychological laboratory for the study of mental and physiological characteristics of temperaments. Kretschmer made a significant contribution to understanding the relationship between the biological and psychological aspects of personality and mental illness.