  The International Ultraviolet Explorer satellite has made a tremendous
contribution to the study of hot-star winds. Its long lifetime has resulted in
the collection of ultraviolet spectra for a large sample of OB stars. Its
unique monitoring capability has enabled detailed time-series analyses to
investigate the stellar-wind variability for individual objects. IUE has also
been a major driver for the development of the radiation-driven-wind theory;
the synergy between theory and observations is one of the main reasons for the
large progress that has been made in our understanding of hot-star winds and
their impact on the atmospheres and evolution of massive stars.
