Overview: Big Bang in the Laboratory; H.H. Gutbrod, J. Rafelski. Physics of Relativistic Nuclear Collisions; I. Otterlund. Towards the LHC; P. Giubellino. Hot Hadronic Matter: Fireball Spectra; U. Heinz, et al. Quark Matter in Equilibrium; F. Karsch. Towards Dynamical Theoretical Description: Cascade Models and Particle Production; J. Cugnon. Relativistic Hydrodynamics and Flavor Flow; L. Csernai, et al. Quark-Gluon Plasma Formation in UltraRelativistic Heavy Ion Collisions; K. Geiger. Diagnostic Methods and Recent Results: A Pedestrian's Guide to Particle Interferometry; W.A. Zajc. Strangeness in Ultrarelativistic NucleusNucleus Collisions; E. Quercigh. On the Trail of Quark-Gluon Plasma; J. Rafelski. Epilogue: The Quark-Gluon Plasma; P.A. Carruthers. 20 additional articles. Index.

Seven years after the first experiments in the new field of Nuclear Physics, the Highly Relativistic Heavy Ion Physics, the Nato-Advanced- Study-Institute on the 'Particle Production in Highly Excited Matter' was held from July 12 till July 24, 1992, at Il Ciocco, Castelvecchio Pascoli, near Lucca in Italy. The school took place at a mo ment when intensive efforts are mounted by the scientific community of Relativistic Heavy Ion Physics to meet the extraordinary challenge of the new upcoming physics opportunities. The gold beams of 10 GeV A at Brookhaven AGS have been sent to the experiments this Summer and we extent our congratulations to the persons and teams who made this possible. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven is under construction and expected to allow experiments to see collisions in the intersec tion regions early 1998. The lead beams at the SPS at CERN scheduled for summer 1994 are eagerly awaited by 6 large experiments, and many scientists are planning the experiments at the planned LHC with heavy ions to be turned on before the year 2000. Seen against this background of rather fierce activity, we were most delighted when NATO accepted our application for an Advanced Study Institute oriented to the main subject of this young and dynamic field of research. We are very grateful to the Scientific Affairs Division of NATO and Dr. L. DaCunha, the director of the Advanced Study Institute program for giving our community this opportunity.

The past decade has seen the development of the operational understanding of fun damental interactions within the standard model. This has detoured our attention from the great enigmas posed by the dynamics and collective behavior of strongly interacting particles. Discovered more than 30 years ago, the thermal nature of the hadronic particle spectra has stimulated considerable theoretical effort, which so far has failed to 'confirm' on the basis of microscopic interactions the origins of this phenomenon. However, a highly successful Statistical Bootstrap Model was developed by Rolf Hagedorn at CERN about 30 years ago, which has led us to consider the 'boiling hadronic matter' as a transient state in the trans formation of hadronic particles into their melted form which we call Quark-GIuon-Plasma (QGP). Today, we return to seek detailed understanding of the thermalization processes of hadronic matter, equipped on the theoretical side with the knowledge of the fundamental strong interaction theory, the quantum chromo-dynamics (QCD), and recognizing the im portant role of the complex QCD-vacuum structure. On the other side, we have developed new experimental tools in the form of nuclear relativistic beams, which allow to create rather extended regions in space-time of Hot Hadronic Matter. The confluence of these new and recent developments in theory and experiment led us to gather together from June 27 to July 1, 1994, at the Grand Hotel in Divonne-Ies-Bains, France, to discuss and expose the open questions and issues in our field.