Non-thermal emission from galaxy clusters: a Pandora's vase for
  astrophysics
  The existence of cosmic rays and weak magnetic fields in the intracluster
volume has been well proven by deep radio observations of galaxy clusters.
However a detailed physical characterization of the non-thermal component of
large scale-structures, relevant for high-precision cosmology, is still
missing. I will show the importance of combining numerical and theoretical
works with cluster observations by a new-generation of radio, Gamma- and X-ray
instruments.
