Going from classic to contemporary authors, the authors of this volume consider theorists that provided contributions that became representative of trends, schools of thought and original theoretical perspectives, and that grew into the backbone of Marxist thought: Karl Marx, Vladimir Lenin, Antonio Gramsci, Edward Palmer Thompson, Nicos Poulantzas, Erik O. Wright, Antonio Negri, and John Holloway, with references to Rosa Luxemburg, Georg Lukacs, Jean-Paul Sartre, and Ralph Miliband. The authors seek to provide a basis for the knowledge of the main contributions in contemporary Marxism and to place the debate on the concept of social class at the center of current sociological reflections. In this sense, the last chapter is not a balance nor an assessment, but offers an exercise in the problematization of the concepts of struggle and class, geared towards highlighting its relevance and potential in Marxist sociology within an agenda centered in the principle of antagonism. Beyond the endeavor to recognize and revitalize the Marxist perspective, the authors offer tools for reflection that allow readers to refresh and expand their knowledge on a fundamental concept and a debate of great theoretical importance in social thought.