"Reform or Revolution” is one of Rosa Luxemburg's major works. It was written in 1898-1899 and is the ‘orthodox’ Marxist response to Eduard Bernstein’s “Problems of Socialism”. Here we start exploring what Bernstein's ideas were in terms of the evolution of Capitalism and how to effectively respond to this evolution. Ideas that Rosa and the Marxists refuted. History proved that both Bernstein and Rosa were right, and that the solution likely lies somewhere in the middle of their respective assessments.