  We discuss the present status of the description of the structure of the very
neutron rich nuclei, in the framework of modern large scale shell model
calculations. Particular attention is paid to the interaction related issues,
as well as to the problems of the shell model approach at the neutron drip
line. We present detailed results for nuclei around N=20 and, more briefly, we
discuss some salient features of the regions close to N=8, 28 and 40. We show
that most experimental features can be understood in a shell model context.
