2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/13954This paper reviews the results from recent optical and near-infrared spectroscopic studies of ultraluminous infrared galaxies.6 pages, 2 embedded figures, Review Talk presented at the September 1998 Ringberg Meeting "Ultraluminous Galaxies: Monsters or Babies?"Astrophysicstext