  We summarize recent developments in modeling of mass outflows from accretion
disks in AGN. We illustrate how the hydrodynamical and magnetohydrodynamical
wind structures revealed in numerical simulations relate to observations.
Important results from the numerical simulations include: no shielding from
X-rays is needed to radiatively launch a wind from the inner disk; shielding is
needed to accelerate the wind to high velocities. Disk winds launched
magnetically seem to be too dense to be accelerated by line driving. It appears
that we have an all or nothing situation for radiation-driving: radiation
driving has to be responsible for both launching and accelerating the wind or a
wind launched by some other mechanism must have a very finely tuned density in
order to be accelerated by radiation driving to velocities as high as measured
in BAL QSOs.
