"Crowds have always played a serious role in history, but never as significant a role as they do today. The unconscious action of crowds, as it comes under the influence of the actions of individuals, represents one of the characteristic features of our era."     In this work, Le Bon formulates his theory on the influence of the mass on the psychology of the individual and lays the foundations for the science of social psychology. All the individual characteristics of a person, such as logic, consciousness, and critical ability, are leveled down within the mass.     Crowds have characteristics entirely different from those of the individuals that compose them. Different personalities merge into a single entity of thought and emotion.     This book had a particular impact on the leaders of the 20th century and contributed to the construction of the fascist regime.