The Winter School "Nuclear Matter and Heavy Ion Collisions", a NATO Research Workshop held at Les Houches in February 89, has been devoted to recent developments in nuclear matter theory and to the study of central heavy ion collisions in which quasi macroscopic nuclear systems can be formed at various temperatures and densities. At in cident energies below 100 Me V per nucleon, the kinematic conditions are favourable for producing transient hot nuclei with temperatures of the order of a few MeV. At higher ener gies (100 MeV weiterlesen