The polysemic nature of the term "populism" means that any study that addresses it as a topic faces the obligation to define it. Thus, Mackinnon and Petrone outline a complete review of the variety of phenomena reached by this term that is used daily in the most diverse contexts: journalism, politics, academia. The articles in this compilation, written by Latin American and Anglo-Saxon authors, address five cases of populism in Latin America: Vargas's Brazil (1945-1954), Cárdenas's Mexico (1934-1940), Peronist Argentina (1945-1955), the Peru of Haya de la Torre's postulates, and Velasco Ibarra's Ecuador.