Modern science is indebted to the renaissance scientists like Bruno, Copernicus, Galileo and many others. They had to face oppressions from the Church for their search for scientific truth. In this monograph the life and struggle of Galileo Galilei for establishing scientific truth have been discussed. It has been discussed how science won a resounding victory over religion.Today when all over the world the capitalist class are encouraging all sorts of blind faiths and superstitions, the struggle of the renaissance scientists will inspire those who want to fight for truth.