Serge Moscovici, leading figure in the field of social psychology and engaged in the study of minorities in this work examines three themes of the first magnitude in the current sociology: the problem of change, the role of social influence in this and the full significance they have minorities as agents of change. Among the merits of this study highlights the success of its wings challenge traditional conceptualizations of social influence and the value of their author to erect solo and consolidated positions critical of discovering a new role for an active minority and "have no need to resign. "