Collective aspects of hadrons and quarks in nucleus-nucleus collisions

The primary goal of colliding heavy nuclei at high energy is to obtain information on the hadronic matter equation of state at high density and temperature. Hydrodynamical models are well suited theoretically for such studies. However, the degree of applicability of such models to realistic size nuclei is still an open question. Comparisons are made between numerical calculations and experiment for Ar+KCl at 800 MeV per nucleon. The prospects for, and consequences of, heavier nuclei and much higher energy are discussed.