  The motivations to make ultraviolet (UV) studies of supernovae (SNe) are
reviewed and discussed in the light of the results obtained so far by means of
IUE and HST observations. It appears that UV studies of SNe can, and do lead to
fundamental results not only for our understanding of the SN phenomenon, such
as the kinematics and the metallicity of the ejecta, but also for exciting new
findings in Cosmology, such as the tantalizing evidence for "dark energy" that
seems to pervade the Universe and to dominate its energetics. The need for
additional and more detailed UV observations is also considered and discussed.
