  We review potential mass-loss mechanisms in the various evolutionary stages
of massive stars, from the well-known line-driven winds of O-stars and
BA-supergiants to the less-understood winds from Red Supergiants. We discuss
optically thick winds from Wolf-Rayet stars and Very Massive Stars, and the
hypothesis of porosity-moderated, continuum-driven mass loss from stars
formally exceeding the Eddington limit, which might explain the giant outbursts
from Luminous Blue Variables. We finish this review with a glance on the impact
of rapid rotation, magnetic fields and small-scale inhomogeneities in
line-driven winds.
