  This review paper discusses the past and present observations of gamma-ray
blazars with both space and ground-based gamma-ray telescopes (such as EGRET
and current TeV telescopes), and with the VLBA. I also discuss the more
sensitive gamma-ray telescopes such as AGILE and GLAST that will become
available over the next several years, and how observations with these
telescopes, together with improved VLBA observations, can increase our
understanding of blazar physics.
