He is a professor of constitutional law at the Complutense University of Madrid. Before it was the universities of Santiago de Compostela, Alicante and Alcalá de Henares. He is the author of the books The Republic and the Liberal State (1977); The crisis of the welfare state (1986); Historical theory of state and constitutional law, 2 vols. (1988 and 1993); Against consensus. Studies on the constitutional state and constitutionalism of the welfare state (1997); The Concept of Law (2001); The Constitutional reform in the perspective of the sources of law (2003), the last two published in this same Editorial, Constitutional Theory and solidarity (2006).