AGN models for the X and gamma-ray backgrounds

The origin of the X-ray background spectral intensity has been a long stand ing problem in high energy astrophysics research. Deep X-ray surveys carrie d out with ROSAT and ASCA combined with the broad band spectral results of Ginga and BeppoSAX satellites strongly support the hypothesis that the bulk of the X-ray background is due to the integrated contribution at discrete sources (mainly AGNs). At higher energies the unexpected findings of the Co mpton Gamma Bay Observatory indicate that also the Cl-ray background is lik ely to be due to AGNs. I will discuss AGN-based models for the high energy backgrounds and how future observations will improve our understanding of t he X- and gamma-ray backgrounds and of the physics and evolution of AGNs.