  The structure of nuclei far off beta-stability is investigated by nuclear
many-body theory. In-medium interactions for asymmetric nuclear matter are
obtained by (Dirac-) Brueckner theory thus establishing the link of nuclear
forces to free space interactions. HFB and RPA theory is used to describe
ground and excited states of nuclei from light to heavy masses. In extreme
dripline systems pairing and core polarization are found to be most important
for the binding, especially of halo nuclei. The calculations show that far off
stability mean-field dynamics is gradually replaced by dynamical correlations,
giving rise to the dissolution of shell structures.
