In 1970 relic radiation from the Big Bang was predicted to interact with intergalactic matter in clusters of galaxies in a manner in which both primordial density fluctuations and the cluster IGM could be characterized. This interaction has now been observed in numerous galaxy clusters.  A great deal of new data on the S-Z effect is now coming in from the South Pole Telescope, the Atacama Cosmology Telescope, the Planck spacecraft, and X-Ray space observatories that are revealing new information about the IGM and cosmology.