The results of Ettore Fiorini include the experimental discovery of the weak nuclear currents; the proposal and first experiment on double-beta decay with Germanium diodes; the first significant limits on nucleon decay, during his direction of NUSEX experiment. He participated, as responsible of the Italian activities, to the Gallex experiment, which first proved the presence of solar neutrinos from proton-proton reactions. His present activity is mainly devoted to the use of thermal detectors in the search of rare events, a technique that he suggested since 1983 and which led to his proposal of the International experiment CUORE, concerning neutrinoless double-beta decay of 130Te and other rare events. National member of the Accademia dei Lincei, he is recipient of the prizes Enrico Fermi and Bruno Pontecorvo, and of the gold medal of the President of the Italian Republic awarded to Benemeriti della Scienza e della Cultura.