Sante De Sanctis (1862—1935), a pioneer of psychology in Rome at the end of the 19th century, applied methods from the expanding field of experimental psychology to the study of dreams, which was considered one of the leading ways to gain an understanding of normal and pathological psychic life. Taking inspiration from several traditions, De Sanctis proposed a study that anticipated a scientific program that also differentiated between contemporary psychoanalytical interpretations according to which previous dream psychology was considered a 'dark (...) forest'. On the contrary, the multi-faceted methodology that he adopted for the study of an, until then, marginal phenomenon of the 'new' psychology, represented an element of originality that also included the elaboration of a psycho-physiological theory of dreams. Although the Italian psychologist's work on dreams was characterized by these important methodological changes, it disappeared from the references of those who contributed to the foundation of modern dreaming psychology after the Second World War. The present article places De Sanctis' psychology of dreams in its scientific context and singles out its originality while also analyzing the reasons for its marginalization. (shrink)