A revolution (from the Latin revolutio, "a turn around") is a fundamental change in power or organizational structures that takes place in a relatively short period of time. Aristotle described two types of political revolution:

Complete change from one constitution to another
Modification of an existing constitution.[1]
Revolutions have occurred through human history and vary widely in terms of methods, duration, and motivating ideology. Their results include major changes in culture, economy, and socio-political institutions.Political and socioeconomic revolutions have been studied in many social sciences, particularly sociology, political sciences and history. Among the leading scholars in that area have been or are Crane Brinton, Charles Brockett, Farideh Farhi, John Foran, John Mason Hart, Samuel Huntington, Jack Goldstone, Jeff Goodwin, Ted Roberts Gurr, Fred Halliday, Chalmers Johnson, Tim McDaniel, Barrington Moore, Jeffery Paige, Vilfredo Pareto, Terence Ranger, Eugen Rosenstock-Huessy, Theda Skocpol, James Scott, Eric Selbin, Charles Tilly, Ellen Kay Trimberger, Carlos Vistas, John Walton, Timothy Wickham-Crowley and Eric Wolf.[13]

Scholars of revolutions, like Jack Goldstone, differentiate four current 'generations' of scholarly research dealing with revolutions.[12] The scholars of the first generation such as Gustave Le Bon, Charles A. Ellwood or Pitirim Sorokin, were mainly descriptive in their approach, and their explanations of the phenomena of revolutions was usually related to social psychology, such as Le Bon's crowd psychology theory.[8]

Second generation theorists sought to develop detailed theories of why and when revolutions arise, grounded in more complex social behavior theories. They can be divided into three major approaches: psychological, sociological and political.[8]

The works of Ted Robert Gurr, Ivo K. Feierbrand, Rosalind L. Feierbrand, James A.