This volume contains the Proceedings of the 17th Workshop of the INFN ELOISATRON Project on "QCD at 200 TeV", held at the "Ettore Majorana" Centre for Scientific Culture, EMCSC, Erice, Trapani, Italy, in the period 11-17 June 1991. The new multi-Te V frontiers of Subnuclear Physics are no more beyond our imagination. A conceptual design of the highest energy (100+100 TeV) proton-proton collider -the ELOISA TRON -already exists. Intensive R & D studies are on the go to develop the most promising and innovative detector technologies for the highest energy and luminosity. QCD (Quantum Chromo-Dynamics) will be the theory to describe the expected Physics scenario of future S upercolliders. The purpose of the Workshop was therefore to review the recent status of QCD in High Energy interactions and to discuss the novel aspects of Perturbative and Non Perturbative QCD with special emphasis on future experimental studies at Super-High Energy Colliders, up to the 200 Te V limit. The topics were: - Classical QCD: particle multiplication, multiplicities and spectra, jet profiles, coherence effects, etc. - Hadron interaction cross-sections and structure functions at Super-High Energies, small-x behaviour, QCD Pomeron, "hot spots"--QCD fragmentation models, present and future. - Artificial neural networks in High Energy Physics. - New theoretical aspects of QCD at Super-High Energies (instanton-induced large cross sections, baryon number violation and peculiar multi-quark production events, etc.)

During July 1990. a group of 83 physicists from 43 laboratories in 21 countries met in Erice for the 28th Course of the International School of Subnuclear Physics. The countries represented were: Algeria. Canada. Chile. China. Czechoslovakia. Denmark. France. the Federal Republic of Germany. Greece. Holland. India. Italy. Pakistan. Peru. Poland. Sweden. Switzerland. Turkey. the Union of Soviet Socialist Republics. the United Kingdom. and the United States of America. The School was sponsored by the European Physical Society (EPS). the Italian Ministry of Education (MPI). the Italian Ministry of University and Scientific Research. the Sicilian Regional Government (ERS). and the Weizmann Institute of Science. The new topic discussed in some detail at the School was QCD phenomenology at 200 TeV. This energy frontier represents the goal for subnuclear physics after LHC and sse. The main lecturers were T.D. Lee. L. Cifarelli. Y. Dokshitzer and A. Ringwald. There are two possibilities. one optimistic. the other pessimistic. LHC and SSC can produce remarkable discoveries. In this case. the need to go to higher energies will be obvious. In the pessimistic case. LHC and SSC will produce the strongest evidence for the validity of the Standard Model. The need for higher energies will be impelled. In neither case can we wait. If the 200 TeV frontier is to be reached within our lifetime we need to start now: thinking and preparing the tools. Theory and R&D for future detectors are the basic points of the 200 TeV frontier.

This is a new text on Quantum Chromodynamics, the theory of the strong force between quarks, the fundamental building blocks of nuclear matter. Although the focus is on experiments, the text also includes anextensive theoretical introduction to the field as well as many exercises with solutions explained in detail.

This book discusses recent developments in both the theoretical and the experimental aspects of QCD. Its main goal is to establish precise predictions of the Standard Model in order to find clues to the discovery of New Physics.

This 2012 volume, now OA, is dedicated to high energy quantum chromodynamics including parton saturation and the color glass condensate.

Recent experimental results and new theoretical developments discussed during the conference are described in these proceedings. The various contributions concern low energy QCD, the most recent advances and challenges in perturbative QCD, the highlights in heavy flavor physics and in QCD at high temperature density. First results from the Bookhaven RHIC machine as well as the latest date from CERN that are providing us with deeper insights into the problem of the quark-gluon plasma and the fascinating issue of the QCD phase diagram are also presented.