He combines his research interests with his position as a sociology professor, and he became the chairman of the Institute for Social Research, for the National School of Political and Social Sciences, also for the Interdisciplinary Research Center in Humanities, at UNAM. He served as President of UNAM from 1970-1972, and has been an invited lecturer at universities such as Cambridge. He was also President of the Asociacion Latinoamericana de Sociología, and belongs to several international societies in sociology. He has published several articles, some of the most influential are Sociología de la explotación (1969), Historia del movimiento obrero en América Latina (1981), El Estado y los partidos políticos en México (1981), América Latina, hoy (1990), El Estado y la política en el sur del mundo (1994), and perhaps the most out standing Democracy in México (1965), which has been translated and edited several times.