... Invited Review Paper. ... In radio-loud AGN, bipolar jets emanating from the nucleus emit radio through gamma-ray light that is relativistically beamed along the jet axes. ... We outline the two most plausible unified schemes for radio-loud AGN, one linking the high-luminosity sources (quasars and luminous radio galaxies) and one the low-luminosity sources (BL~Lac objects and less luminous radio galaxies). ... Table of contents (Postscript file, 38Kb) . ... Postscript versions of all the figures: . ...