Relativity, Quantum Mechanics and Quantum Statistics : 9783659511202 : 25 Jan 2014 : To combine the formulas of GR and QM to calculate something, the same answer is always yielded: infinity, still unsolved. The issue of space-time curvature, Problem of quantization, Universe is non-local or local, particles are zero dimensional or what?, Background of space-time and matter, superposition of states and so on are few of unsolved problems of QM and Relativity. We have observed a relation between reciprocity and quantum statistics. Reciprocity may be a bridge between QM and Relativity which is a great unsolved problem. We have defined Reciprocal Symmetry and we have applied it to find an invariant under addition. This invariant quantity is either an upper bound of a set of quantities or a lower bound of the reciprocals of this set. The set bounded above together with this invariant quantity corresponds to Einstein's postulate. we find that discreteness is directly related Einstein's postu