The eighth Annual Pezcoller Symposium, entitled Genomic Instability and Immor tality in Cancer, was held in Trento, Italy, June 17-19, 1996 and was focused on the clari fication of the mechanisms of genetic instability, a characteristic of neoplastic cells which also determines tumor progression, and immortality consequent to the lack of susceptibil ity to mechanisms of maturations, senescence and/or apoptosis. With presentations at the cutting edge of progress and stimulating discussions, this symposium addressed issues related to mutational lability, changes in DNA repair capa bilities, gene recombination processes, cell cycle checkpoints and apoptosis, the signifi cance of telomerases in cell immortalization and senescence, and the clinical relevance and exploitation of the phenomena considered. We wish to thank the participants in the symposium for their substantial contribu tions and their participation in the spirited discussions that followed. We would also like to thank Drs. Carol Greider, Garth Anderson, Margherita Bignami, and David Livingston, for their essential input as members of the Program Committee, and Ms. A. Toscani for her invaluable assistance. The aid of the Savings Bank Cassa di Risparmio di Trento e Ro vereto, and the Municipal, Provincial, and Regional Administrations in supporting this Symposium through the Pezcoller Foundation are also acknowledged with deep apprecia tion. Finally, we wish to thank the staff of Plenum Publishing Corporation for their effi cient cooperation in the production of these proceedings.