The quest for many-body techniques and approximations to describe the essential physics of strongly interacting systems with many degrees of freedom is one of the central themes of contemporary nuclear physics. The three articles in this volume describe advances in this quest in three dif- ferent areas of nuclear many-body physics: multi quark degrees of freedom in nucleon-nucleon interactions and light nuclei, multinucleon clusters in many-nucleon wave functions and reactions, and the nuclear-shell model. In each case the common issues arise of identifying the relevant degrees of freedom,...

The two comprehensive reviews in this volume address two fundamental problems that have been of long-standing interest and are the focus of current effort in contemporary nuclear physics: exploring experimentally the density distributions of constituents within the nucleus and understand ing nuclear structure and interactions in terms of hadronic degrees of freedom. One of the major goals of experimental probes of atomic nuclei has been to discover the spatial distribution of the constituents within the nucleus. As the energy and specificity of probes have increased over the years, the degree...

Nuclear many-body theory provides the foundation for understanding and exploiting the new generation of experimental probes of nuclear structure that are now becoming available. The twentieth volume of Advances in Nuclear Physics is thus devoted to two major theoretical chapters addressing two fundamental issues: understanding single-particle properties in nuclei and the consistent formulation of a relativistic theory appropriate for hadronic physics. The long-standing problem of understanding single-particle behavior in a strongly interacting nuclear system takes on new urgency and sig...