2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12393The IUE contribution to the understanding of the blazar phenomenon has been of fundamental importance. Here I review the progress obtained with the latest multifrequency campaigns performed with IUE on two prototype objects, the BL Lac PKS 2155-304 and the highly polarized, superluminal quasar 3C 279.6 pages, LATEX, esapub format, 5 postscript figures, to appear in the Proceedings of the Conference 'Ultraviolet Astrophysics Beyond the IUE Final Archive', held in Sevilla, Spain (1997 November 11-14)Astrophysicstext