The authors, through careful reconstructions and research, describe the family circumstances and history of Freud's patient, "Katharina," whom they identify as daughter of the proprietors of a summer hotel in Reichenau where Freud vacationed. They discuss her subsequent history and that of her family. They find that the encounter with Katharina had many implications for the development of Freud's thinking on free association and for the development of the seduction theory.