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.)

The present volume is based on the proceedings of the 6th and 7th INFN ELOISATRON project workshops, held at the Centro di Cultura Scientifica "Et tore Majorana" CCSEM, Erice-Trapani, Sicily, Italy, in the period June 10-27, 1988. The topics of the two workshops were, respectively: - Heavy Flavours: Status and Perspectives, and - Novel Features of High Energy Collisions in 1-100 TeV Region. They were attended by sixty-three physicists. The two workshops were followed by a meeting of the INFN ELOISATRON working group, also held at the CCSEM in the period October 7-15, 1988 in which twenty-five physicists participated. Since there was quite a bit of overlap among speakers, participants and the topics covered at the three meetings, we have decided to issue ajoint proceeding, with the first part entitled: Heavy Flavour Physics, and the second: High Energy Physics with 1-100 Te V Proton Beams. Some of the reports included in this volume have been contributed by the INFN ELOISATRON working group members. The first. part of these proceedings deals mostly with the presentation and inter pretation of results in t.he so-called fiavour physics sector. New results, which have become available in the last three years from experiments involving kaons, charmed and beauty hadrons, and searches for the still missing top quark at the present and fothcoming colliders are topics of major interest. here. The contributions in this part are organized in three categories: Experimental Results, Theoretical Interpretation, and Future Directions.

This workshop brought together for the first time accelerator experts as well as experimental and theoretical high energy physicists from all over the world to consider the physics potential of high energy linear electron-positron colliders. A wide variety of physics cases were presented ranging from precision tests of the top quark and electroweak gauge bosons to searches of the intermediate mass Higgs bosons and supersymmetric particles.

This volume is a collection of review articles on the most outstanding topics in heavy flavour physics. All the authors have made significant contributions to this field. The book reviews in detail the theoretical structure of heavy flavour physics within the Standard Model and its confrontation with existing experimental data.The physics of the top quark and of the Higgs play an important role in this volume. Beginning with radiative electroweak corrections and their impressive tests at LEP and hadron colliders, the book summarizes the present status of quark mixing, CP violation and rare decays. The dynamics of exclusive D- and B-meson decays, the τ-lepton physics and the newly discovered heavy quark symmetries are discussed in detail. The impact of strong interactions on weak decays is clearly visible in many articles. The physics of heavy flavours at LEP, HERA and hadron colliders constitutes an important part of the book. Another significant topic is the possible role of heavy flavours in the spontaneous symmetry breaking of gauge symmetries. Finally the most recent advances in lattice calculations of the properties of heavy flavours and the lattice studies of the dynamics of heavy flavours are presented.