  Fresh insights and powerful numerical tools are revitalizing the theoretical
exploration of the supernova mechanism. The realization that the protoneutron
star is Rayleigh-Taylor unstable at various times and radii and, hence, that a
multi-dimensional perspective is required is one agent of this revolution.
However, a new physical understanding of the nature of explosions (even
spherical explosions) that are driven by neutrino heating and that escape from
deep within a gravitational potential well is also emerging. This, together
with the new multi-dimensional approach, promises to establish a paradigm
within which supernova explosions and their consequences can be studied in the
future.
