Mass Loss and Evolution of Massive Stars

I discuss the early observations and the discovery of stellar winds from massive stars, including the development of wind theories, the effects of mass loss on stellar evolution, the role of rotation and the evolutionary connection between different types of massive stars. Because of the special nature of this conference, I will put some emphasis on the role of Utrecht astronomers. Some unsolved problems will be discussed: (a) the dependence of mass loss on metallicity in relation to the evolution of the first generation stars (b) the dependence of mass loss on rotation and the formation of GRBs and (c) the onset of winds in stars with barely sufficient radiation pressure.