  We present a review of recent applications of the relativistic mean-field
theory to the structure of nuclei close to the drip-lines. For systems with
extreme isospin values, the relativistic Hartree-Bogoliubov model provides a
unified and self-consistent description of mean-field and pairing correlations.
The model has been applied in studies of structure phenomena that include:
formation of neutron skin and of neutron halos in light nuclei in the mass
region above the s-d neutron shell, the strong isospin dependence of the
effective spin-orbit interaction and the resulting modification of surface
properties, the suppression of the spherical N=28 shell gap for neutron-rich
nuclei and the related phenomenon of deformation and shape coexistence, the
proton drip-line in the spherical nuclei $14\leq Z \leq 28$, and ground-state
proton radioactivity in the region of deformed nuclei $59 \leq Z \leq 69$.
