Book excerpt: Ch. 1. Double beta decay - historical retrospective and perspectives. 1.1. From the early days until the gauge theory era. 1.2. The nuclear physics side - nuclear matrix elements. 1.3. Double beta decay, neutrino mass models and cosmological parameters - status and prospects. 1.4. Other beyond standard model physics : from SUSY and leptoquarks to compositeness and space time structure. 1.5. The experimental race : from the late eighties to the discovery of [symbol] decay. 1.6. The future of double beta decay. 1.7. Conclusion -- ch. 2. Original articles. 2.1. From the early days until the gauge theory era. 2.2. The nuclear physics side - nuclear matrix elements. 2.3. Double beta decay, neutrino mass models and cosmological parameters - status and prospects. 2.4. Other beyond standard model physics : from SUSY and leptoquarks to compositeness and space time structure. 2.5. The experimental race : from the late eighties to the discovery of [symbol] decay. 2.6. The future of double beta decay