The Role of Neutrinos Strings Gravity and Variable Cosmological Constant in Elementary Particle Physics th The 29 International Conference was held as the first one of the millennium at its Fort Lauderdale venue. These conferences began with High Energy Physics being the main topic by introducing gradually cosmology into its programs. These proceedings of the 2000 conference reflect the variety of topics and ideas discussed. Our future conferences will be designed somewhat akin to the early Coral Gables Conferences where we shall seek some convergence of ideas. For this reason various committees have been formed from among the participating physicists. The committees and their memberships are listed in these proceedings. We further decided for the first time to include some graduate student participants in our future meetings for which also a committee has already been established. The topics will demonstrate a more activist structure of the Coral Gables Conferences for example the duality of the gravitational forces and expansion of the universe will be discussed from this point of view since it conveys a convergence to the ideas of quintessence versus the ordinary theory which are considered as the cause of the expansion of the universe. We further wish to announce that the future conferences will assume a collective organization where several committees as listed in these proceedings will have their input into the conference. We have now introduced new topics and ideas which referred especially to the attractive and repulsive nature of the gravitational force. These proceedings of the conference contain a variety of topics and ideas. The Cosmological Constant is not Really a Constant Recent Developments in Gravitational Theory and an Intrinsic Cosmological Parameter Quintessence and Cosmic Microwave Background Cosmic Acceleration and a Natural Solution to the Cosmological Constant Problem Beyond the Standard Model Spontaneous Violation of Lorentz and CPT Symmetry Topics in Lorentz and CPT Violation Dark Matter Caustics Manifest Supersymmetry and Background Ramond FLux Neutrino Physics and Cosmology Supernova II Neutrino Bursts and Neutrino Massive Mixing A Neutrino Component of Ultra High Energy Cosmic Rays Probing the Nature of Neutrinos at Pion Factories Inclusive Neutrino and Antineutrino Reactions in Iron and an Interesting Relation Nature’s Highest Energy Particle Accelerators Nature’s Highest Energy Particle Accelerators The Origin of all Cosmic Rays: A Space Filling Mechanism Primordial Black Holes and the Asymmetrical Distribution of Short GRB Events Exploring the Extreme Universe with the Gamma Ray Large Area Space Telescope The Latest Developments in High Energy Physics and Cosmology Comments on Supersymmetry Extra Dimensions and the Accelerating Universe Field Theory Correlators and String Theory A Microscopic Basis for the Entropy of AdS3 Black Hole CP Violation in B—Decays Status and Prospects of $$ \\bar B $$ New Experiment on Spinning Protons’ Violent Collisions The Grand Unified Theory of Classical Quantum Mechanics.