In the abundance spectrum of r-process nuclei the most prominent features are the peaks that form when the r-process flow passes through the closed neutron shells .
However , there are also other features in the abundance spectrum that can not be explained by shell effects , like the peak in the region of the rare-earth nuclei around mass A = 160 .
It has been argued that this peak is related to the deformation maximum of the neutron-rich isotopes .
Recently , both experimental and theoretical work has been carried out to study the deformation of neutron-rich rare-earth nuclei and to search for the point of maximum deformation .
This work has focused on the nuclei around ^ { 170 } Dy in order to understand the evolution of collectivity in the neutron shell with 82 < N < 126 .
These investigations will be discussed in terms of the Harris parameters of the Variable Moment of Inertia model .
Finally , we will discuss the future possibilities to reach further into the neutron-rich rare-earth region at the new experimental facilities using radioactive beams .