Type la Supernovae have taken on a leading role in measuring extra-galactic distances providing key information about the Hubble Constant and providing evidence of an accelerating Universe. Unfortunately these conclusions are based on an empirical relationship between SN brightness and light curve shape rather than any deep physical understanding. A key ingredient to gaining physical understanding lies in understanding what becomes a SN la progenitor. Essentially all models require a binary system to push a white dwarf higher in mass. I will review the current attempts observational and theoretical to pin down the nature of these important astrophysical objects.