  In years to come, we shall see substantial progress in our understanding of
nuclear structure - a rich and many-faceted field. An important element in this
task will be to extend the study of nuclei into new domains. The journey to
'the limits' of isospin, angular momentum, and mass and charge is a quest for
new and unexpected phenomena which await us in uncharted territories. What is
extremely important from a theoretical point of view is that the new data are
also expected to bring qualitatively new information about the effective
nucleon-nucleon interaction and hence about the fundamental properties of the
nucleonic many-body system. The main objective of this presentation is to
discuss some of the challenges and opportunities for nuclear structure research
with radioactive nuclear beams.
