Scrutiny of experimental observations of bending of EM radiation, one of the determinant proofs of General Relativity, suggests a clue of profound significance; gravity appears to deflect EM radiation proportionally to its frequency. Differences in deflections of light in the visible spectrum and microwave radiation are minimal, but de facto under an accurate statistical exam. The GEM Experiment described in the book, patent released in December 2022 by the Italian ``Ministero delle Imprese e del Made in Italy'', aims to definitely validate this theory. The proposed system employs a tunable source of gamma-rays, about the Higgs resonance, as the one tendered by the LHC facilities at CERN. The gamma-ray source is tunable for being tunable the energy employed to let Hadrons collide. This is essential to check extra deflections occurring as the Hadron collision energy is modulated. The proposal is based on a critical discussion of the prescriptions suggested by the general theory of relativity. Clues lead to the resurrection of an Ether-like concept, not in the sense of a rigid structure where drifting through, but as a frame where things of Nature show their existence. This eventually suggests a quantum approach based on a graviton conjecture. In particular GR is not seen as a theory encompassing Newtonian mechanics, but as a correction to classical dynamics, still missing of the Gravito-Electro-Magnetic (GEM) interaction; that is the conjectured interaction between Gravitational and Electro-Magnetic forces. The proposed theory wants then to eke the general theory of relativity on adding a NNLO correction to the NLO one provided by GR to Newtonian dynamics. The validity of this model, definitely substantiated by the outcome of the proposed Experiment, will finally complete the general theory of relativity, by-passing any demonstrative weakness of the most recent PPN formalisms, and eventually tendering a new way of construing Physics.