  Cosmic explosions are observed in many astrophysical environments. They range
in scale from hydromagnetic instabilities in the terrestrial magnetotail and
solar ``nanoflares'' to cosmological gamma ray bursts, supernovae and the
protracted intervals of nuclear activity that produce the giant quasars and
radio galaxies. There are many parallels in the analyses of the explosion sites
that are highlighted at this workshop, specifically stellar coronae, accretion
disks, supernovae and compact objects. In this introductory talk, some general
issues are discussed and some more specific questions relating to the
individual sites are raised.
