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