Psychoanalysis, aside from being a therapeutic science, is a historical science: it is concerned not only with man himself, but also with his biography, the products of his intellect and of his hands. As historical research, it has adopted research methods proper to history: documents are collected and supplemented with biographical data, connections are woven together and processes are established. But it does not stop at this point: it seeks to understand, through the study of documentary material, the workings of the mind, beyond direct observation. Documents are treated as "signs" and "manifestations" of this world of representations, of fantasies and forces that constitute the ultimate matrix of subjective individual events and historical events. The research method is, at this level, the same that is used to decipher the unconscious world and dream messages: the recounted, experienced, or certified events are considered to be dreams or fragments of dreams, effects of condensation, moving, schisms, and fragmentations carried out by the thought process.