This volume contains three review articles written by some of the foremost experts in the world and pertaining to three different problems of great current interest for nuclear physics. One article deals with the origin of spin in the quark model for neutrons and protons, as measured with beams of electrons and muons. Another deals with the current evidence for liquid-to-gas phase transitions in relativistic collisions of nuclei. The third deals with the very unusual bands of energy levels of very high spin which are found when nuclei achieve a very high rotation.