  At least one neutrino has a mass of about 50 meV or larger. However, the
absolute mass scale for the neutrino remains unknown. Furthermore, the critical
question: Is the neutrino its own antiparticle? is unanswered. Studies of
double beta decay offer hope for determining the absolute mass scale. In
particular, zero-neutrino double beta decay (\BBz) can address the issues of
lepton number conservation, the particle-antiparticle nature of the neutrino,
and its mass. A summary of the recent results in \BBz, and the related
technologies will be discussed in the context of the future \BBz\ program.
