Modern elementary particle theories. Accelerator particle physics The early universe and particle physics. Proton decay. Neutron-antineutron oscillations, and electric dipole moment of the neutron. Experiments to determine the neutrino mass. Neutrino oscillations. Magnetic monopoles. The search for dark matter in the universe. Particles with a fractional charge. Fifth force: theoretical expectations and experimental status. Time dependence of natural constants. Bibliography. Index.