The Quest for Neutrino-less Double Beta Decay

We review the status and future of ongoing searches for neutrino-less double beta decay, a lepton-number violating nuclear decay whose existence would imply that neutrinos are their own antiparticles, i.e Majorana particles. The measurement of its decay rate is arguably the most sensitive laboratory probe of the absolute mass of neutrinos. Emphasis is given to the most promising detector technologies in the field which aim at exploring the inverted hierarchy region of neutrino masses.