  Galactic winds from star-forming galaxies play at key role in the evolution
of galaxies and the inter-galactic medium. They transport metals out of
galaxies, chemically-enriching the inter-galactic medium and modifying the
chemical evolution of galaxies. They affect the surrounding inter-stellar and
circum-galactic media, thereby influencing the growth of galaxies through gas
accretion and star-formation. In this contribution we first summarize the
physical mechanisms by which the momentum and energy output from a population
of massive stars and associated supernovae can drive galactic winds. We use the
proto-typical example of M82 to illustrate the multiphase nature of galactic
winds. We then describe how the basic properties of galactic winds are derived
from the data, and summarize how the properties of galactic winds vary
systematically with the properties of the galaxies that launch them. We
conclude with a brief discussion of the broad implications of galactic winds.
