The determination of the properties of the neutrino is one of the most pursued goals of physics. The series of MEDEX Conferences, which started ten years ago, is devoted to the update of the experimental and theoretical information related to the nuclear double beta decay, which is the process that may, if observed, be the tool to answer the fundamental questions related to the neutrino mass scale. MEDEX is a unique forum for theoreticians and experimentalists active in the field.