  In this paper, we deal with the subject of piezonuclear reactions, namely
nuclear reactions (of new type) triggered by pressure waves. We discuss the
experimental evidences obtained in the last two decades, which can be
summarized essentially as follows: experiments in cavitation of liquids, where
transmutation of elements, creation of elements and emission of neutrons have
been observed; emission of neutrons in brittle failure of solids subjected to
mechanical pressure; alteration of the lifetime of un unstable element
(thorium) subjected to cavitation. A theoretical model to explain these facts
is proposed. Future perspectives of these experimental and theoretical
investigations are also underlined.
