Based on the premise that the work with groups has always had a very close relationship with the social, political and cultural context, and its transformations, this dissertation aims to develop a psychoanalytical investigation on the large groups of contemporary times, from a socio-historical point of view. In order to do so, it first looks into the dicotomies that polarized individual-society relationships in the 19th and 20th centuries, criticizing the modern individualism. Next it presents more integrated viewpoints of such relationships through the sociological theories of Georg Simmel and Norbert Elias, which were fundamental to the construction of the theoretical framework of group analysis. In the sequence, the research focuses on the emergence of crowd psychology in France, in the 19th century, moving into the investigation of mass society, mass-man and Freudian mass psychology, characteristic of the 20th century, and finally reaches the discussion of large groups in the 21st century. Taking historical changes as background, this dissertation shows how different views of the same phenomenon were built – the crowds / the masses / the large groups –, a conceptual development that, nowadays, favors the concept of the social unconscious. The social unconscious is the offspring of recent researches by a group of psychoanalysts and group analysts and has been a significant theoretical-clinical tool in the investigations of conflicts amid large groups, massive traumas and transgenerational psychic transmission in societies.