The proceedings contain the lectures and contributions given at the workshop on double-beta decay and related topics, which was held at the ETC∗ (European Centre for Theoretical Studies), Trento, Italy, between April 24 and May 5, 1995.Double-beta decay is of prominent actuality nowadays. With the largely increased actuality of neutrino physics by recent observations and discussions of solar and atmospheric neutrino deficits, dark matter physics and neutrino oscillations and recent corresponding development in Grand Unified Theories, double-beta decay has attained a key position within these problems. The lectures of this Workshop treat the theoretical and experimental status, potential and perspectives of double-beta decay research and the intimate interrelations with the above mentioned and other topics from the view of particle, nuclear and astrophysics.