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Although the first evidence for activity in the nuclei of galaxies came from early 20th century optical observations,it was the discovery of radio galaxies with their enormous energy requirements that drew broad attention to the nature of galactic nuclei.But,it was the 1963 discovery of quasars that focused attention to the likely existence of supermassive black holes(SMBH)as the source of energy in what are now called Active Galactic Nuclei(AGN).We will review the radio properties of AGN with particular emphasis on the relativistic beaming which is manifested by rapid flux density variability and apparent superluminal radio jets,and conclude with a summary of the outstanding unsolved issues.