This technical book describes a unified theory of Gravitation, ElectroMagnetism and the Strong interactions (GEMS). This theory provides explicit color confinement, and provides a formulation of gravity that modifies gravity on the galactic scale with results similar to MoND - Modified Newtonian Gravity but without the sacrifice of conventional principles of mechanics or quantum theory. With the introduction of ElectroMagnetism we find a new mechanism for gluon-photon interactions that may solve the long-standing ‘missing proton spin’ puzzle. The combined theory is consistent with our knowledge of these forces. We also show that there is strong circumstantial evidence to abandon ElectroWeak theory and view fundamental physics as based on the combination of GEMS and an independent SU(2) Weak interaction theory.