Salvador López Arnal is professor-tutor of mathematics of the UNED and professor of computer science of Formative Cycles in the IES Puig Castellar of Santa Coloma de Gramenet, Barcelona. He regularly collaborates in the pages of El Viejo Topo, without permission, Papers of ecosocial relations and global change and Dialectics, as well as in www.rebelión.org and www.moviments.net/espaimarx. He is co-author, together with Eduard Rodríguez Farré, of Almost everything you want to know about the effects of nuclear energy on health and the environment (El Viejo Topo, Barcelona, 2008) and editor of Manuel Sacristán on Dialectical Envelope (The Viejo Topo, Barcelona, 2008) and, together with Pere de la Fuente, about About Manuel Sacristán (Destination, Barcelona, 1996). He was co-writer, together with Joan Benach and Xavier Juncosa, of the eight documentaries, directed by the latter, collected under the general title Integral Sacristán (El Viejo Topo, Barcelona, 2007).