• the connection of models of nuclear physics with interacting nucleons and mesons to the quark-gluon picture; 
• the special role of the pion within QCD and the development of effective field theories at low energies;
• the detailed understanding of light nuclei (2H, 3He) to interpret deep inelastic electron-scattering experiments (where these nuclei provide neutron targets to allow the study of the quark structure of the neutron) or, at lower energies, to interpret high precision electron-scattering experiments (which may knock out nucleons and fingerprint the carriers of the nuclear force and currents); 
• the study of hadron-hadron collisions which, contrarily to electron scattering experiments probing only the charge and the magnetism of the quark distributions, probe also gluon distributions.
• the progeny of exotic short-lived, neutron or proton rich nuclei in supernovae explosions, and the halo structure of largely extended weakly-bound nuclei.
• the nature of high-density matter, the identification of the transition to the deconfined or quark-gluon plasma phase.

The study of nuclear few-body systems goes across the mentioned problems of Nuclear Physics. It evolved from a highly specialized area of Nuclear Physics, mainly oriented towards the numerical resolution of equations for two- and three-nucleon systems, the first step towards handling complexity, to a broader field, where the interest has shifted to a more fundamental and microscopic understanding of the underlying dynamics. Nowadays one also witnesses endeavours to push the frontiers of numerical methods for two- and three-nucleon bound and scattering states to larger and more complex systems. 

• light nuclei are ideal for probing the microscopic aspects of nuclear structure, related to quarks and gluons. 
• they are specially important in astrophysics, elementary particle physics and energy production since most of matter in the visible Universe is in the form of light nuclei. They are the protagonists in the nuclear physics of conventional stars and in the nuclear physics reactions triggered after the Big Bang. 
• the 2H e 3He nuclei are the best available providers of neutron targets. Reactions with these targets are a unique tool to study the differences between the neutron and proton quark structure. A direct way to probe this structure is through electron deep-inelastic scattering.

Over the years, the nuclear force has been extensively studied by scattering one nucleon from another. In this way, a few succesful parametrizations of the low-energy nucleon-nucleon force emerged. Nevertheless, they differ in their assumptions about the short-range behavior, where the interface with QCD is critical. Furthermore, even the best available parametrization of the nucleon-nucleon force cannot explain nuclear binding. To explain the experimental binding energies of the simplest light nuclei, a three-body force has to be added to the pairwise interactions determined from two nucleon scattering.

Two types of experiments are decisive to probe this short-range nuclear dynamics: 

1. electron scattering experiments, for which continuous electron beam accelerators and large-acceptance detectors were recently developed (TJNAF);
2. Meson production at threshold experiments for which proton storage rings with internal targets and cooling techniques were built (CELSIUS and COSY).

In summary, the experimental and theoretical study of static and dynamic properties of few-hadron systems is crucial to our knowledge of the nucleon-nucleon and also the three-nucleon interaction, which in turn is the basis of our understanding of general nuclear structure and nuclear reactions. As for recent and ongoing developments, the views based on Perturbative Chiral Effective Field Theories rooted on power counting rules first proposed by Weinberg, seem finally to rescue Nuclear Physics from the old problems of regularization and renormalization.