Professor George Rosensteel is a major contributor to the area of the application of symmetries and group theoretical techniques to nuclear structure physics. He proposes to investigate the microscopic origin of nuclear collective modes by utilizing the symplectic, microscopic collective model, based upon the Sp(3,R) Lie algebra, and the theory of Riemann ellipsoids as theoretical tools. The goal of this project is to discover the fundamental microscopic physics underlying geometrical collective modes in nuclei. This investigation will provide a better understanding of how shell considerations and nucleon pairing influence and modify the hydrodynamic behavior of nuclei, as assumed by Bohr and Mottelson in their collective model.