Despite the fact that atomic nuclei are complex many-body objects, influenced strongly by two forces, and densely packed with orbiting nucleons, they yet exhibit striking regularities, simple patterns and, in some cases, manifest many-body dynamical symmetries. One of the overarching goals of nuclear structure studies is to uncover these simple patterns experimentally and to delineate the symmetries they reflect. This is an effort to understand what nuclei are doing. The flip side is to understand this simple behavior microscopically in terms of nucleonic motion and interactions. The goal here is to understand why nuclei do what they do. These approaches are complementary not competitive. Much progress has been made in recent years along both fronts.