For many years Maxwell's equations were mute testimony to the Lorentz coordinate transformations of special relativity, but the significance of this transformation was not fully understood until relativity itself had been discovered. The author of this book claims that an oversight has once again occurred in fundamental physics. A direct link between Quantum Mechanics and Gravity - perhaps the biggest scientific enigma of all time - has been overlooked. In an entirely novel approach to Quantum-Gravity, this book suggests that Gravity is the manifestation of a very weak non-linearity in Quantum Mechanics; a non-linearity only apparent in the presence of large quantities of matter or very condensed wave functions. The reader will discover how this non-linearity is a natural consequence of a particular interpretation of the Quantum Equations. This book however, does not share the same genre of totalising theories that emphatically and triumphantly declare a new dawn. Instead its thesis can only present itself as a fascinating hypothesis submitted for consideration. Should the theory presented here prove its mettle, then it would provide the key to opening up new vistas of theoretical and experimental research, thus helping to clear the conceptual log jam in which contemporary fundamental physics finds itself.