  I present the elements of accretion-disc physics applied to active galactic
nuclei. The accretion driving mechanisms are discussed, then models of
geometrically-thin discs, both stationary and time-dependent, are addressed.
Disc's self-gravitation in the AGN context is presented. The shapes of spectral
line from accretion discs are explained in both newtonian and relativistic
cases. The physics of disc's thermal and viscous instabilities is dicussed in
detail and models are applied to AGN discs. Finally, the problems of thick
accretion flows (ADAFs and slim discs), disc coronae, winds and jets are
discussed in some detail. This is a graduate-student level lecture, not a
review article
