Clusters of galaxies are the largest relaxed systems in the Universe,
and contain hundreds of galaxies a regions which are several Mpc across.
Remarkably, the stars and galaxies by which these objects were first
identified constitute only a small fraction (a few percent) of their
mass.  The dominant form of baryonic matter is clusters is hot (10**8 K)
intracluster gas, which has more mass than the stars and galaxies by a
factor of about 5.  The properties of clusters of galaxies and their X-ray
emission will be reviewed.  I will describe some recent results on two
aspects of the nonthermal and thermal content of the intracluster medium.
First, the results of recent searches with Suzaku for nonthermal Inverse
Compton (IC) emission from clusters will be presented.  The X-ray bright,
nearby galaxy clusters Coma and Abell 3667 host the brightest radio
halo (Coma) and radio relic (A3667) known.  These diffuse, Mpc-scale
structures are due to synchrotron emission from relativistic electrons,
which also produce hard X-ray inverse Compton (IC) emission.  The high
sensitivity and narrow FOV of the Suzaku PIN Hard X-ray Detector makes
it an ideal instrument to search for IC.  Second, I will discuss recent
radio and X-ray observations of the central regions of cool core clusters.
The nature of the interaction for the central radio sources and X-ray
gas will be described.