The authors locate August Aichhorn's pioneering ideas about the psychodynamics and psychotherapy of adolescents in the context of psychoanalytic pedagogy in Europe in the 1920s and '30s. Strongly influenced by Freud's discoveries and theory, Aichhorn was himself a major influence on the work of Anna Freud and of many other child and adolescent psychoanalytic theoreticians, including Spitz, Mahler, Eissler, Erikson, and Blos. His technique drew heavily on the element of surprise and on the adolescent patient's identification with the analyst, as well as on the use of humor and empathy in treatment. The authors utilize brief vignettes from Aichhorn's descriptions of his practice to illustrate his unique clinical style.