2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42322The present experimental status in the search for neutrinoless double beta decay is reviewed, with emphasis on the first indication for neutrinoless double beta decay found in the HEIDELBERG-MOSCOW experiment, giving first evidence for lepton number violation and a Majorana nature of the neutrinos. Future perspectives of the field are briefly outlined.42 pages, latex, 21 figures, To be Published in Indian National Science Academy (INSA) - Special issue: Neutrinos, (2003) eds. D. Indumathi, G. Rajasekaran and M.V.N. Murthy; see also Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc/High Energy Physics - Phenomenologytext