"Psychology of the Masses" is the second part of the fundamental work of Gustave Lebon, written in 1895, which provides a detailed analysis of the psychology of the broad masses (in this case, the crowd) as the most important motive for individual behavior and the cause of historical events. Crowd psychology has become a branch of social psychology that studies the behavior of groups of people and differences in the behavior of the crowd and its individual persons (individuals). We are talking about sudden social changes caused by the actions of large groups of people, which would not be inherent to one participant in the events.