Massive stars lose mass through powerful, radiatively driven stellar winds. Building on the original "CAK" model for steady, spherical winds driven by line-scattering, this talk will review recent research on the multi-faceted nature of such wind mass loss under varied conditions, for example due to rapid rotation, magnetic channeling, binary interaction, or a luminosity near the Eddington limit. An overall theme is that wind mass loss can in this way lead to a wide variety of astrophysical phenomena, including bipolar nebulae, massive star magnetospheres, colliding winds or compact companion accretion, and luminous blue variable eruption. The discussion here will summarize these with an emphasis on their varied observational signatures.