The author uses Freud's 1905 work, Three Essays on the Theory of Sexuality, as the basis of his observations. He indicates that Freud's conclusions about adolescence were derived more from anecdotal and historical material than from actual subjects. Although he states that Freud was concerned primarily with the third of the essays, "The Transformations of Puberty," later in his article Klumpner maintains that the key to the origin of Freud's ideas about adolescence can be found in the second essay. Freud usually used the inductive method to arrive at his conclusions, but in regard to adolescence he used the deductive method. Klumpner supports his thesis by systematically showing how Freud's theories of adolescence did not arise from: 1) observations of his own children; 2) his self-analysis; or 3) his clinical work with adolescents.