Retrospective of Research with Reinhard Schlickeiser

I give a summary of my research with Prof. Dr. Reinhard Schlickeiser. It mainly took place in the 1990s, when the Compton Gamma Ray Observatory was giving a startling new view of the gamma-ray sky. Our work focused on particle acceleration and radiation processes in the jets of active galactic nuclei (AGN). We pioneered the external Compton scattering model of blazars, where photons from outside the jet are intercepted and scattered to high energies by the radio-emitting electrons within the jet. Although we originally focused on external photons from the accretion disks of AGN, this process has been extended to include a range of external photon sources, and is now established as the primary source of gamma rays from flat spectrum radio quasars.