Daniel J. Lennon . ... How do massive stars and stellar populations evolve? What are the roles of mass-loss, rotation, binarity and magnetic fields? How does massive star evolution depend on metal content and environment? ... Key Words & Phrases: Massive stars, winds, atmospheres, rotation, massive binaries, chemical composition, star clusters, extra-galactic stellar spectroscopy, large-scale spectroscopic surveys, resolved stellar in nearby galaxies, stellar evolution . ...