Recent advances in three areas of nuclear physics are addressed in this volume. The theory of the ground state of matter is fundamental to many areas of physics and, in particular, is crucial to a microscopic understanding of nuclear physics. All conclusions concerning the relevance of me sonic, nu­ clear isobar, and quark degrees of freedom to nuclear structure are nec­ essarily subject to limitations in one's ability to accurately solve the nuclear many-body problem with static two-body interactions. Thus, it is particularly significant that in recent years great advances have been made in the vari­ ational theory of the ground state of zero-temperature infinite matter. The first article presents a pedagogical treatment of these advances and surveys computational results for a variety of model and physical systems. The second article reviews recent progress in determining nuclear tran­ sition densities from inelastic electron scattering. In the past, detailed knowl­ edge of the charge distributions in nuclear ground states obtained from inverting elastic electron scattering data has proven extremely valuable.