César Ruiz Sanjuán is Professor of Philosophy at the Complutense University of Madrid. He has carried out research stays in Germany and the United States, and has translated and edited several philosophical works from German and English. His research activity has focused mainly on the thought of Marx and the main currents of Marxism, also dealing with authors such as Hegel, John Stuart Mill, Gramsci, Polanyi or Hannah Arendt, on which he has published numerous articles in specialized journals and has participated in collective books and conferences. Currently his academic work is oriented to the fields of political philosophy and social philosophy.