  Some recent results on the physical and statistical properties of nearby and
distant AGN are presented. I first discuss the properties of "elusive" AGNs,
i.e. obscured AGNs which do not show a Seyfert-like spectrum in the optical.
Then I present preliminary results from a detailed study of the contribution of
obscured AGNs and of their host galaxies to the infrared cosmic background.
Finally I discuss an observational program aimed at investigating the
properties of the most distant quasars, of their circumnuclear medium and the
implications for their host galaxies.
