Experimental and theoretical nuclear structure physics. My research focuses on the structural evolution of the atomic nucleus as a function of the numbers of its constituent protons and neutrons including quantum phase transitions in nuclear shapes, the evolution of the underlying shell structure, and the emergence of collective behavior . One aim is to identify the remarkable regularities and simple patterns exhibited by these complex quantal many-body systems and to describe them in terms of the symmetries and quantum numbers applicable to the system as a whole. At the next level, we try to understand the origin of these regularities in terms of the interactions of the nucleons, especially the valence proton-neutron interaction. The experimental component of the research looks especially to the properties of newly accessible exotic nuclei far from the valley of stable nuclei.