  We will discuss the properties and origins of halos and relics including
estimates of the cluster magnetic fields, and present results for a few
recently discovered halos and relics. The electrons in the suprathermal high
energy tail of the thermal gas distribution are likely to provide the seed
particles for acceleration through mergers and turbulences to relativistic
energies. These relativistic particles are then responsible for the synchrotron
emission of the halos.
