2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12999The nature of the extremely red galaxies is poorly known, the critical issue being whether they are old ellipticals at $z>1.5$ or distant star-forming galaxies strongly reddened by dust extinction. Here we review the little we know about them, and we present recent and preliminary results from our ongoing submillimeter -- millimeter observations.4 pages, 1 figure. To appear in the proceedings of the Xth Rencontres de Blois: The Birth of Galaxies; Blois, France, July 1998Astrophysicstext