In the now prevalent idea of hierarchical structure formation,  galaxy 
clusters form the youngest population and the present is the epoch of 
cluster mergers. Such mergers may involve energies up to 10^{64} ergs: 
they are the major heating source of the intra-cluster medium and can 
accelerate particles up to relativistic energies. 
XMM-Newton and Chandra have allowed to observe with an unprecedented 
detail clusters undergoing mergers. Thanks to their combined high spectral 
and spatial resolution it has been possible to study in detail the 
two-dimensional distribution of thermodynamic quantities (density, 
temperature, pressure and entropy).
I will present the thermodynamic maps of a sample of 19 nearby (z<0.1) 
merging clusters. 
Often, massive merging clusters show extended radio emission. The 
relativistic particles, responsible of synchrotron emission, can interact 
with the photons of the CMB and produce Inverse Compton radiation, which 
could be detected in hard X-rays. I will discuss the observations of the 
Coma cluster in hard X-rays, performed by the PDS instrument on board 
Beppo SAX.