This research on Gaitanismo and the events of April 9 is an updated critical review based on the wealth of historiographic documentation about the emergence of the Gaitanista social mobilization, the role of its leader, Jorge Eliecer Gaitan, the meaning of his murder, and the characterization of the complex process of insurrection and popular uprising in Bogota and other Colombian regions and cities. The article places what has been considered as the most important event of Colombia’s political history in the XXth century in its international context and in the complex sociopolitical web in which the Gaitanista movement was created.