  Cluster mergers drive shocks into the intracluster medium which heat and
compress the thermal gas. X-ray observations of shocks can be used to determine
the geometry and kinematics of the merger. Merger shocks should also accelerate
relativistic particles. Electrons with gamma about 300 (E about 150 MeV) are
expected to be particularly common. Relativistic particles produce observed EUV
emission, hard X-ray tails, and diffuse radio emission. The predicted gamma-ray
fluxes of clusters should make them easily observable with GLAST.
