2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/126140I briefly review the theoretical models of radiatively efficient, geometrically thin and optically thick accretion disk spectra that currently exist for AGN. I then discuss three recent observational developments that have real potential to teach us about the physics of these flows. Finally, I present results on the most recent, thermodynamically consistent simulations of magnetorotational turbulence and discuss what these simulations are suggesting about the vertical structure of accretion disks.Review Talk, to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang, (San Francisco: ASP)Astrophysicstext