  Observations of Type Ia supernovae (SN~Ia) combined with modeling of
dynamics, light curves and spectra continue to point to the difficult
conclusion that SN~Ia result from degenerate ignition in a carbon/oxygen white
dwarf of the Chandrasekhar mass. Such a model accounts well for the ``normal"
SN~Ia and for the observed dispersion exemplified by the light curve
amplitude-shape relation. The criterion that the white dwarfs involved in this
process grow to nearly 1.4 Msun continues to provide a great challenge to
understanding the binary stellar evolution involved. The so-called ``supersoft
X-ray sources" may provide an important new population of SN~Ia progenitors.
Other techniques are being developed that may constrain the binary evolution.
