  The current status of understanding of the X-ray emission from Seyfert
galaxies involves thermal Comptonization of soft photons by mildrelativistic
electrons and positrons. I review observational and theoretical arguments
supporting such a view, discussing current models proposed for the structure of
the innermost part of the accretion flow: extended coronae, small scale flaring
blobs, advection dominated accretion disks and small scale cold cloudlets.
