TOPOLOGICAL DEFECTS AND HIGHEST ENERGY COSMIC AND GAMMA-RAYS

In this paper we review the hypothesis that a substantial part of the cosmic ray flux observed above about 10(19) eV may be produced by deca ying or annihilating topological defects left over from phase transiti ons in the early universe at grand unification energy scales (approxim ate to 10(16) GeV). Possible signatures of cosmic ray producing defect models are discussed which could be tested experimentally in the near future. We thereby focus on model independent universal spectral prop erties of the predicted particle fluxes.