The hidden sides of the nucleus

This dossier treats in a digest way of the recent advances in the study of nuclei: the study of exotic nuclei and its stakes in the understanding of matter and of the Universe; the historical changes of nuclei models through a retrospective of the main scientists who contributed to their elaboration; the questioning of the nuclei stability valley by recent discoveries; the high-technology facilities for the production of exotic nuclei; a new kind of radioactivity: the two-proton decay; the strange shapes of nuclei: pear, banana, saucer; the halo and cluster nuclei and their associated theories. (J.S.)