I address the issue of nonthermal processes in the large scale structure of the universe. After reviewing the properties of cosmic shocks and their role as particle accelerators, I discuss the main observational results, from radio to ɤ-ray and describe the processes that are thought be responsible for the observed nonthermal emissions. Finally, I emphasize the important role of ɤ-ray astronomy for the progress in the field. Non detections at these photon energies have already allowed us important conclusions. Future observations will tell us more about the physics of the intracluster medium, shocks dissipation and CR acceleration.

• FRANCESCO MINIATI(Dept. of Physics, ETH)