Borexino is mainly a solar neutrino experiment, currently running at the Laboratori Nazionali del Gran Sasso. It is the best detector in operation and it is made of 300t of ultrapure liquid scintillator. Thanks to almost two decades of R&D, the core of the scintillator is now the less radioactive object existing on Earth. Borexino has already obtained important results on low energy solar neutrinos and it is supposed to continue data taking for several years. Its exceptional features make Borexino also suitable for other physics tasks, such as, e.g., the SOX project. The Genova group has a leading role in the project (spoke-person Prof. M. Pallavicini) and over almost 20 years has taken responsibility of many crucial items, such as the electronics, the data acquisition, the triggering system, the scintillator characterization, simulation, and data analysis.