Arnon Dar is a Professor of Physics since 1968 at the department of physics and the Asher Space Research Institute of the Technion, Israel Institute of Technology, in Haifa and is the incumbent of the Naite and Beatrice Sherman Chair in physics. He received his Ph.D. in 1964 from the Weizmann Institute of Science in Rehovot for inventing the Diraction model of Direct nuclear reactions and its generalization to high energy particle reactions. Later he worked on the quark model of elementary particles and its applications to particle decays and the interactions of high energy particles, including nuclei. In the late 1970's, he became interested in neutrino physics and neutrino astronomy. Since the early 1980's his main research interests became particle astrophysics and cosmology, particularly astrophysical and cosmological tests of the standard models of particle-physics, general relativity and cosmology. These included studies of cosmic puzzles such as the solar neutrino puzzle, the origin of cosmic rays and gamma ray bursts, and the nature of dark matter and dark energy. He suggested the Day-Night Eect in solar neutrinos, tests of neutrino oscillations with atmospheric neutrinos, and gravitational lensing tests of general relativity at very large distances. In collaboration with various authors, he suggested the existence of cosmic backgrounds of MeV neutrinos from stellar evolution, and past supernova explosions, and of a high energy cosmic neutrino and gamma ray background radiations from interactions of cosmic rays in galaxies and in the intergalactic medium. In recent years, he has been working on a unied theory of high energy cosmic accelerators, gamma ray bursts and cosmic ray origin and implications to astrobiology and the terrestrial environment. His research was conducted at the Technion and at CERN, MIT, the Institute for Advanced Studies in Princeton, NASA/GSFC, MPI/Munchen, University of Paris at Orsay, University of Pennsylvania and Cambridge University, during long visiting appointments there. He published more than 150 scientic papers in these various elds in professional journals and gave more than 150 invited talks published in the proceedings of international conferences. He served the Technion as a chairman of the physics department, a chairman of the Technion faculty and a member of Technion's board of governors. He also served as a member of Israel Defense Ministry committees and Israel Atomic Energy Committee and of several national and international scientic committees and advisory boards. Many of his Ph.D students became full professors in leading universities in Israel and abroad.